cc/trees/layer_tree_impl.cc

   1 // Copyright 2011 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "cc/trees/layer_tree_impl.h"
   6
   7 #include <algorithm>
   8 #include <limits>
   9 #include <set>
  10
  11 #include "base/trace_event/trace_event.h"
  12 #include "base/trace_event/trace_event_argument.h"
  13 #include "cc/animation/keyframed_animation_curve.h"
  14 #include "cc/animation/scrollbar_animation_controller.h"
  15 #include "cc/animation/scrollbar_animation_controller_linear_fade.h"
  16 #include "cc/animation/scrollbar_animation_controller_thinning.h"
  17 #include "cc/base/math_util.h"
  18 #include "cc/base/synced_property.h"
  19 #include "cc/base/util.h"
  20 #include "cc/debug/devtools_instrumentation.h"
  21 #include "cc/debug/traced_value.h"
  22 #include "cc/input/page_scale_animation.h"
  23 #include "cc/layers/heads_up_display_layer_impl.h"
  24 #include "cc/layers/layer.h"
  25 #include "cc/layers/layer_iterator.h"
  26 #include "cc/layers/render_surface_impl.h"
  27 #include "cc/layers/scrollbar_layer_impl_base.h"
  28 #include "cc/resources/ui_resource_request.h"
  29 #include "cc/trees/layer_tree_host_common.h"
  30 #include "cc/trees/layer_tree_host_impl.h"
  31 #include "cc/trees/occlusion_tracker.h"
  32 #include "ui/gfx/geometry/point_conversions.h"
  33 #include "ui/gfx/geometry/size_conversions.h"
  34 #include "ui/gfx/geometry/vector2d_conversions.h"
  35
  36 namespace cc {
  37 // This class exists to split the LayerScrollOffsetDelegate between the
  38 // InnerViewportScrollLayer and the OuterViewportScrollLayer in a manner
  39 // that never requires the embedder or LayerImpl to know about.
  40 class LayerScrollOffsetDelegateProxy : public LayerImpl::ScrollOffsetDelegate {
  41  public:
  42   LayerScrollOffsetDelegateProxy(LayerImpl* layer,
  43                                  LayerScrollOffsetDelegate* delegate,
  44                                  LayerTreeImpl* layer_tree)
  45       : layer_(layer), delegate_(delegate), layer_tree_impl_(layer_tree) {}
  46   virtual ~LayerScrollOffsetDelegateProxy() {}
  47
  48   gfx::ScrollOffset last_set_scroll_offset() const {
  49     return last_set_scroll_offset_;
  50   }
  51
  52   // LayerScrollOffsetDelegate implementation.
  53   void SetCurrentScrollOffset(const gfx::ScrollOffset& new_offset) override {
  54     last_set_scroll_offset_ = new_offset;
  55   }
  56
  57   gfx::ScrollOffset GetCurrentScrollOffset() override {
  58     return layer_tree_impl_->GetDelegatedScrollOffset(layer_);
  59   }
  60
  61   bool IsExternalFlingActive() const override {
  62     return delegate_->IsExternalFlingActive();
  63   }
  64
  65   void Update() const override {
  66     layer_tree_impl_->UpdateScrollOffsetDelegate();
  67   }
  68
  69  private:
  70   LayerImpl* layer_;
  71   LayerScrollOffsetDelegate* delegate_;
  72   LayerTreeImpl* layer_tree_impl_;
  73   gfx::ScrollOffset last_set_scroll_offset_;
  74 };
  75
  76 LayerTreeImpl::LayerTreeImpl(
  77     LayerTreeHostImpl* layer_tree_host_impl,
  78     scoped_refptr<SyncedProperty<ScaleGroup>> page_scale_factor,
  79     scoped_refptr<SyncedTopControls> top_controls_shown_ratio,
  80     scoped_refptr<SyncedElasticOverscroll> elastic_overscroll)
  81     : layer_tree_host_impl_(layer_tree_host_impl),
  82       source_frame_number_(-1),
  83       hud_layer_(0),
  84       currently_scrolling_layer_(NULL),
  85       root_layer_scroll_offset_delegate_(NULL),
  86       background_color_(0),
  87       has_transparent_background_(false),
  88       overscroll_elasticity_layer_(NULL),
  89       page_scale_layer_(NULL),
  90       inner_viewport_scroll_layer_(NULL),
  91       outer_viewport_scroll_layer_(NULL),
  92       page_scale_factor_(page_scale_factor),
  93       min_page_scale_factor_(0),
  94       max_page_scale_factor_(0),
  95       elastic_overscroll_(elastic_overscroll),
  96       scrolling_layer_id_from_previous_tree_(0),
  97       contents_textures_purged_(false),
  98       viewport_size_invalid_(false),
  99       needs_update_draw_properties_(true),
 100       needs_full_tree_sync_(true),
 101       next_activation_forces_redraw_(false),
 102       has_ever_been_drawn_(false),
 103       render_surface_layer_list_id_(0),
 104       top_controls_shrink_blink_size_(false),
 105       top_controls_height_(0),
 106       top_controls_shown_ratio_(top_controls_shown_ratio) {
 107 }
 108
 109 LayerTreeImpl::~LayerTreeImpl() {
 110   BreakSwapPromises(SwapPromise::SWAP_FAILS);
 111
 112   // Need to explicitly clear the tree prior to destroying this so that
 113   // the LayerTreeImpl pointer is still valid in the LayerImpl dtor.
 114   DCHECK(!root_layer_);
 115   DCHECK(layers_with_copy_output_request_.empty());
 116 }
 117
 118 void LayerTreeImpl::Shutdown() {
 119   root_layer_ = nullptr;
 120 }
 121
 122 void LayerTreeImpl::ReleaseResources() {
 123   if (root_layer_) {
 124     LayerTreeHostCommon::CallFunctionForSubtree(
 125         root_layer_.get(), [](LayerImpl* layer) { layer->ReleaseResources(); });
 126   }
 127 }
 128
 129 void LayerTreeImpl::RecreateResources() {
 130   if (root_layer_) {
 131     LayerTreeHostCommon::CallFunctionForSubtree(
 132         root_layer_.get(),
 133         [](LayerImpl* layer) { layer->RecreateResources(); });
 134   }
 135 }
 136
 137 void LayerTreeImpl::GatherFrameTimingRequestIds(
 138     std::vector<int64_t>* request_ids) {
 139   if (!root_layer_)
 140     return;
 141
 142   // TODO(vmpstr): Early out if there are no requests on any of the layers. For
 143   // that, we need to inform LayerTreeImpl whenever there are requests when we
 144   // get them.
 145   LayerTreeHostCommon::CallFunctionForSubtree(
 146       root_layer_.get(), [request_ids](LayerImpl* layer) {
 147         layer->GatherFrameTimingRequestIds(request_ids);
 148       });
 149 }
 150
 151 void LayerTreeImpl::SetRootLayer(scoped_ptr<LayerImpl> layer) {
 152   if (inner_viewport_scroll_layer_)
 153     inner_viewport_scroll_layer_->SetScrollOffsetDelegate(NULL);
 154   if (outer_viewport_scroll_layer_)
 155     outer_viewport_scroll_layer_->SetScrollOffsetDelegate(NULL);
 156   inner_viewport_scroll_delegate_proxy_ = nullptr;
 157   outer_viewport_scroll_delegate_proxy_ = nullptr;
 158
 159   root_layer_ = layer.Pass();
 160   currently_scrolling_layer_ = NULL;
 161   inner_viewport_scroll_layer_ = NULL;
 162   outer_viewport_scroll_layer_ = NULL;
 163   page_scale_layer_ = NULL;
 164
 165   layer_tree_host_impl_->OnCanDrawStateChangedForTree();
 166 }
 167
 168 LayerImpl* LayerTreeImpl::InnerViewportScrollLayer() const {
 169   return inner_viewport_scroll_layer_;
 170 }
 171
 172 LayerImpl* LayerTreeImpl::OuterViewportScrollLayer() const {
 173   return outer_viewport_scroll_layer_;
 174 }
 175
 176 gfx::ScrollOffset LayerTreeImpl::TotalScrollOffset() const {
 177   gfx::ScrollOffset offset;
 178
 179   if (inner_viewport_scroll_layer_)
 180     offset += inner_viewport_scroll_layer_->CurrentScrollOffset();
 181
 182   if (outer_viewport_scroll_layer_)
 183     offset += outer_viewport_scroll_layer_->CurrentScrollOffset();
 184
 185   return offset;
 186 }
 187
 188 gfx::ScrollOffset LayerTreeImpl::TotalMaxScrollOffset() const {
 189   gfx::ScrollOffset offset;
 190
 191   if (inner_viewport_scroll_layer_)
 192     offset += inner_viewport_scroll_layer_->MaxScrollOffset();
 193
 194   if (outer_viewport_scroll_layer_)
 195     offset += outer_viewport_scroll_layer_->MaxScrollOffset();
 196
 197   return offset;
 198 }
 199
 200 scoped_ptr<LayerImpl> LayerTreeImpl::DetachLayerTree() {
 201   // Clear all data structures that have direct references to the layer tree.
 202   scrolling_layer_id_from_previous_tree_ =
 203     currently_scrolling_layer_ ? currently_scrolling_layer_->id() : 0;
 204   if (inner_viewport_scroll_layer_)
 205     inner_viewport_scroll_layer_->SetScrollOffsetDelegate(NULL);
 206   if (outer_viewport_scroll_layer_)
 207     outer_viewport_scroll_layer_->SetScrollOffsetDelegate(NULL);
 208   inner_viewport_scroll_delegate_proxy_ = nullptr;
 209   outer_viewport_scroll_delegate_proxy_ = nullptr;
 210   inner_viewport_scroll_layer_ = NULL;
 211   outer_viewport_scroll_layer_ = NULL;
 212   page_scale_layer_ = NULL;
 213   currently_scrolling_layer_ = NULL;
 214
 215   render_surface_layer_list_.clear();
 216   set_needs_update_draw_properties();
 217   return root_layer_.Pass();
 218 }
 219
 220 void LayerTreeImpl::PushPropertiesTo(LayerTreeImpl* target_tree) {
 221   // The request queue should have been processed and does not require a push.
 222   DCHECK_EQ(ui_resource_request_queue_.size(), 0u);
 223
 224   if (next_activation_forces_redraw_) {
 225     target_tree->ForceRedrawNextActivation();
 226     next_activation_forces_redraw_ = false;
 227   }
 228
 229   target_tree->PassSwapPromises(&swap_promise_list_);
 230
 231   target_tree->set_top_controls_shrink_blink_size(
 232       top_controls_shrink_blink_size_);
 233   target_tree->set_top_controls_height(top_controls_height_);
 234   target_tree->PushTopControls(nullptr);
 235
 236   // Active tree already shares the page_scale_factor object with pending
 237   // tree so only the limits need to be provided.
 238   target_tree->PushPageScaleFactorAndLimits(nullptr, min_page_scale_factor(),
 239                                             max_page_scale_factor());
 240   target_tree->elastic_overscroll()->PushPendingToActive();
 241
 242   target_tree->pending_page_scale_animation_ =
 243       pending_page_scale_animation_.Pass();
 244
 245   if (page_scale_layer_ && inner_viewport_scroll_layer_) {
 246     target_tree->SetViewportLayersFromIds(
 247         overscroll_elasticity_layer_ ? overscroll_elasticity_layer_->id()
 248                                      : Layer::INVALID_ID,
 249         page_scale_layer_->id(), inner_viewport_scroll_layer_->id(),
 250         outer_viewport_scroll_layer_ ? outer_viewport_scroll_layer_->id()
 251                                      : Layer::INVALID_ID);
 252   } else {
 253     target_tree->ClearViewportLayers();
 254   }
 255
 256   target_tree->RegisterSelection(selection_start_, selection_end_);
 257
 258   // This should match the property synchronization in
 259   // LayerTreeHost::finishCommitOnImplThread().
 260   target_tree->set_source_frame_number(source_frame_number());
 261   target_tree->set_background_color(background_color());
 262   target_tree->set_has_transparent_background(has_transparent_background());
 263
 264   if (ContentsTexturesPurged())
 265     target_tree->SetContentsTexturesPurged();
 266   else
 267     target_tree->ResetContentsTexturesPurged();
 268
 269   if (ViewportSizeInvalid())
 270     target_tree->SetViewportSizeInvalid();
 271   else
 272     target_tree->ResetViewportSizeInvalid();
 273
 274   if (hud_layer())
 275     target_tree->set_hud_layer(static_cast<HeadsUpDisplayLayerImpl*>(
 276         LayerTreeHostCommon::FindLayerInSubtree(
 277             target_tree->root_layer(), hud_layer()->id())));
 278   else
 279     target_tree->set_hud_layer(NULL);
 280
 281   target_tree->has_ever_been_drawn_ = false;
 282 }
 283
 284 LayerImpl* LayerTreeImpl::InnerViewportContainerLayer() const {
 285   return inner_viewport_scroll_layer_
 286              ? inner_viewport_scroll_layer_->scroll_clip_layer()
 287              : NULL;
 288 }
 289
 290 LayerImpl* LayerTreeImpl::OuterViewportContainerLayer() const {
 291   return outer_viewport_scroll_layer_
 292              ? outer_viewport_scroll_layer_->scroll_clip_layer()
 293              : NULL;
 294 }
 295
 296 LayerImpl* LayerTreeImpl::CurrentlyScrollingLayer() const {
 297   DCHECK(IsActiveTree());
 298   return currently_scrolling_layer_;
 299 }
 300
 301 void LayerTreeImpl::SetCurrentlyScrollingLayer(LayerImpl* layer) {
 302   if (currently_scrolling_layer_ == layer)
 303     return;
 304
 305   if (currently_scrolling_layer_ &&
 306       currently_scrolling_layer_->scrollbar_animation_controller())
 307     currently_scrolling_layer_->scrollbar_animation_controller()
 308         ->DidScrollEnd();
 309   currently_scrolling_layer_ = layer;
 310   if (layer && layer->scrollbar_animation_controller())
 311     layer->scrollbar_animation_controller()->DidScrollBegin();
 312 }
 313
 314 void LayerTreeImpl::ClearCurrentlyScrollingLayer() {
 315   SetCurrentlyScrollingLayer(NULL);
 316   scrolling_layer_id_from_previous_tree_ = 0;
 317 }
 318
 319 namespace {
 320
 321 void ForceScrollbarParameterUpdateAfterScaleChange(LayerImpl* current_layer) {
 322   if (!current_layer)
 323     return;
 324
 325   while (current_layer) {
 326     current_layer->ScrollbarParametersDidChange(false);
 327     current_layer = current_layer->parent();
 328   }
 329 }
 330
 331 }  // namespace
 332
 333 float LayerTreeImpl::ClampPageScaleFactorToLimits(
 334     float page_scale_factor) const {
 335   if (min_page_scale_factor_ && page_scale_factor < min_page_scale_factor_)
 336     page_scale_factor = min_page_scale_factor_;
 337   else if (max_page_scale_factor_ && page_scale_factor > max_page_scale_factor_)
 338     page_scale_factor = max_page_scale_factor_;
 339   return page_scale_factor;
 340 }
 341
 342 void LayerTreeImpl::SetPageScaleOnActiveTree(float active_page_scale) {
 343   DCHECK(IsActiveTree());
 344   if (page_scale_factor()->SetCurrent(
 345           ClampPageScaleFactorToLimits(active_page_scale)))
 346     DidUpdatePageScale();
 347 }
 348
 349 void LayerTreeImpl::PushPageScaleFromMainThread(float page_scale_factor,
 350                                                 float min_page_scale_factor,
 351                                                 float max_page_scale_factor) {
 352   PushPageScaleFactorAndLimits(&page_scale_factor, min_page_scale_factor,
 353                                max_page_scale_factor);
 354 }
 355
 356 void LayerTreeImpl::PushPageScaleFactorAndLimits(const float* page_scale_factor,
 357                                                  float min_page_scale_factor,
 358                                                  float max_page_scale_factor) {
 359   DCHECK(page_scale_factor || IsActiveTree());
 360   bool changed_page_scale = false;
 361   if (page_scale_factor) {
 362     DCHECK(!IsActiveTree() || !layer_tree_host_impl_->pending_tree());
 363     changed_page_scale |=
 364         page_scale_factor_->PushFromMainThread(*page_scale_factor);
 365   }
 366   if (IsActiveTree())
 367     changed_page_scale |= page_scale_factor_->PushPendingToActive();
 368   changed_page_scale |=
 369       SetPageScaleFactorLimits(min_page_scale_factor, max_page_scale_factor);
 370
 371   if (changed_page_scale)
 372     DidUpdatePageScale();
 373 }
 374
 375 void LayerTreeImpl::set_top_controls_shrink_blink_size(bool shrink) {
 376   if (top_controls_shrink_blink_size_ == shrink)
 377     return;
 378
 379   top_controls_shrink_blink_size_ = shrink;
 380   if (IsActiveTree())
 381     layer_tree_host_impl_->UpdateViewportContainerSizes();
 382 }
 383
 384 void LayerTreeImpl::set_top_controls_height(float top_controls_height) {
 385   if (top_controls_height_ == top_controls_height)
 386     return;
 387
 388   top_controls_height_ = top_controls_height;
 389   if (IsActiveTree())
 390     layer_tree_host_impl_->UpdateViewportContainerSizes();
 391 }
 392
 393 bool LayerTreeImpl::SetCurrentTopControlsShownRatio(float ratio) {
 394   ratio = std::max(ratio, 0.f);
 395   ratio = std::min(ratio, 1.f);
 396   return top_controls_shown_ratio_->SetCurrent(ratio);
 397 }
 398
 399 void LayerTreeImpl::PushTopControlsFromMainThread(
 400     float top_controls_shown_ratio) {
 401   PushTopControls(&top_controls_shown_ratio);
 402 }
 403
 404 void LayerTreeImpl::PushTopControls(const float* top_controls_shown_ratio) {
 405   DCHECK(top_controls_shown_ratio || IsActiveTree());
 406
 407   if (top_controls_shown_ratio) {
 408     DCHECK(!IsActiveTree() || !layer_tree_host_impl_->pending_tree());
 409     top_controls_shown_ratio_->PushFromMainThread(*top_controls_shown_ratio);
 410   }
 411   if (IsActiveTree()) {
 412     if (top_controls_shown_ratio_->PushPendingToActive())
 413       layer_tree_host_impl_->DidChangeTopControlsPosition();
 414   }
 415 }
 416
 417 bool LayerTreeImpl::SetPageScaleFactorLimits(float min_page_scale_factor,
 418                                              float max_page_scale_factor) {
 419   if (min_page_scale_factor == min_page_scale_factor_ &&
 420       max_page_scale_factor == max_page_scale_factor_)
 421     return false;
 422
 423   min_page_scale_factor_ = min_page_scale_factor;
 424   max_page_scale_factor_ = max_page_scale_factor;
 425
 426   return true;
 427 }
 428
 429 void LayerTreeImpl::DidUpdatePageScale() {
 430   if (IsActiveTree())
 431     page_scale_factor()->SetCurrent(
 432         ClampPageScaleFactorToLimits(current_page_scale_factor()));
 433
 434   set_needs_update_draw_properties();
 435
 436   if (root_layer_scroll_offset_delegate_) {
 437     root_layer_scroll_offset_delegate_->UpdateRootLayerState(
 438         TotalScrollOffset(), TotalMaxScrollOffset(), ScrollableSize(),
 439         current_page_scale_factor(), min_page_scale_factor_,
 440         max_page_scale_factor_);
 441   }
 442
 443   ForceScrollbarParameterUpdateAfterScaleChange(page_scale_layer());
 444
 445   HideInnerViewportScrollbarsIfNearMinimumScale();
 446 }
 447
 448 void LayerTreeImpl::HideInnerViewportScrollbarsIfNearMinimumScale() {
 449   if (!InnerViewportContainerLayer())
 450     return;
 451
 452   LayerImpl::ScrollbarSet* scrollbars =
 453       InnerViewportContainerLayer()->scrollbars();
 454
 455   if (!scrollbars)
 456     return;
 457
 458   for (LayerImpl::ScrollbarSet::iterator it = scrollbars->begin();
 459        it != scrollbars->end();
 460        ++it) {
 461     ScrollbarLayerImplBase* scrollbar = *it;
 462     float minimum_scale_to_show_at =
 463         min_page_scale_factor() * settings().scrollbar_show_scale_threshold;
 464     scrollbar->SetHideLayerAndSubtree(
 465         current_page_scale_factor() < minimum_scale_to_show_at);
 466   }
 467 }
 468
 469 SyncedProperty<ScaleGroup>* LayerTreeImpl::page_scale_factor() {
 470   return page_scale_factor_.get();
 471 }
 472
 473 const SyncedProperty<ScaleGroup>* LayerTreeImpl::page_scale_factor() const {
 474   return page_scale_factor_.get();
 475 }
 476
 477 gfx::SizeF LayerTreeImpl::ScrollableViewportSize() const {
 478   if (!InnerViewportContainerLayer())
 479     return gfx::SizeF();
 480
 481   return gfx::ScaleSize(InnerViewportContainerLayer()->BoundsForScrolling(),
 482                         1.0f / current_page_scale_factor());
 483 }
 484
 485 gfx::Rect LayerTreeImpl::RootScrollLayerDeviceViewportBounds() const {
 486   LayerImpl* root_scroll_layer = OuterViewportScrollLayer()
 487                                      ? OuterViewportScrollLayer()
 488                                      : InnerViewportScrollLayer();
 489   if (!root_scroll_layer || root_scroll_layer->children().empty())
 490     return gfx::Rect();
 491   LayerImpl* layer = root_scroll_layer->children()[0];
 492   return MathUtil::MapEnclosingClippedRect(layer->screen_space_transform(),
 493                                            gfx::Rect(layer->content_bounds()));
 494 }
 495
 496 void LayerTreeImpl::ApplySentScrollAndScaleDeltasFromAbortedCommit() {
 497   DCHECK(IsActiveTree());
 498
 499   page_scale_factor()->AbortCommit();
 500   top_controls_shown_ratio()->AbortCommit();
 501   elastic_overscroll()->AbortCommit();
 502
 503   if (!root_layer())
 504     return;
 505
 506   LayerTreeHostCommon::CallFunctionForSubtree(
 507       root_layer(), [](LayerImpl* layer) {
 508         layer->ApplySentScrollDeltasFromAbortedCommit();
 509       });
 510 }
 511
 512 void LayerTreeImpl::SetViewportLayersFromIds(
 513     int overscroll_elasticity_layer_id,
 514     int page_scale_layer_id,
 515     int inner_viewport_scroll_layer_id,
 516     int outer_viewport_scroll_layer_id) {
 517   overscroll_elasticity_layer_ = LayerById(overscroll_elasticity_layer_id);
 518   page_scale_layer_ = LayerById(page_scale_layer_id);
 519   DCHECK(page_scale_layer_);
 520
 521   inner_viewport_scroll_layer_ =
 522       LayerById(inner_viewport_scroll_layer_id);
 523   DCHECK(inner_viewport_scroll_layer_);
 524
 525   outer_viewport_scroll_layer_ =
 526       LayerById(outer_viewport_scroll_layer_id);
 527   DCHECK(outer_viewport_scroll_layer_ ||
 528          outer_viewport_scroll_layer_id == Layer::INVALID_ID);
 529
 530   HideInnerViewportScrollbarsIfNearMinimumScale();
 531
 532   if (!root_layer_scroll_offset_delegate_)
 533     return;
 534
 535   inner_viewport_scroll_delegate_proxy_ = make_scoped_ptr(
 536       new LayerScrollOffsetDelegateProxy(inner_viewport_scroll_layer_,
 537                                          root_layer_scroll_offset_delegate_,
 538                                          this));
 539
 540   if (outer_viewport_scroll_layer_)
 541     outer_viewport_scroll_delegate_proxy_ = make_scoped_ptr(
 542         new LayerScrollOffsetDelegateProxy(outer_viewport_scroll_layer_,
 543                                            root_layer_scroll_offset_delegate_,
 544                                            this));
 545 }
 546
 547 void LayerTreeImpl::ClearViewportLayers() {
 548   page_scale_layer_ = NULL;
 549   inner_viewport_scroll_layer_ = NULL;
 550   outer_viewport_scroll_layer_ = NULL;
 551 }
 552
 553 bool LayerTreeImpl::UpdateDrawProperties(bool update_lcd_text) {
 554   if (!needs_update_draw_properties_)
 555     return true;
 556
 557   // Calling UpdateDrawProperties must clear this flag, so there can be no
 558   // early outs before this.
 559   needs_update_draw_properties_ = false;
 560
 561   // For max_texture_size.  When the renderer is re-created in
 562   // CreateAndSetRenderer, the needs update draw properties flag is set
 563   // again.
 564   if (!layer_tree_host_impl_->renderer())
 565     return false;
 566
 567   // Clear this after the renderer early out, as it should still be
 568   // possible to hit test even without a renderer.
 569   render_surface_layer_list_.clear();
 570
 571   if (!root_layer())
 572     return false;
 573
 574   {
 575     TRACE_EVENT2(
 576         "cc", "LayerTreeImpl::UpdateDrawProperties::CalculateDrawProperties",
 577         "IsActive", IsActiveTree(), "SourceFrameNumber", source_frame_number_);
 578     LayerImpl* page_scale_layer =
 579         page_scale_layer_ ? page_scale_layer_ : InnerViewportContainerLayer();
 580     bool can_render_to_separate_surface =
 581         (layer_tree_host_impl_->GetDrawMode() !=
 582          DRAW_MODE_RESOURCELESS_SOFTWARE);
 583
 584     ++render_surface_layer_list_id_;
 585     LayerTreeHostCommon::CalcDrawPropsImplInputs inputs(
 586         root_layer(), DrawViewportSize(),
 587         layer_tree_host_impl_->DrawTransform(), device_scale_factor(),
 588         current_page_scale_factor(), page_scale_layer,
 589         elastic_overscroll()->Current(IsActiveTree()),
 590         overscroll_elasticity_layer_, resource_provider()->max_texture_size(),
 591         settings().can_use_lcd_text, settings().layers_always_allowed_lcd_text,
 592         can_render_to_separate_surface,
 593         settings().layer_transforms_should_scale_layer_contents,
 594         settings().verify_property_trees,
 595         &render_surface_layer_list_, render_surface_layer_list_id_);
 596     LayerTreeHostCommon::CalculateDrawProperties(&inputs);
 597   }
 598
 599   {
 600     TRACE_EVENT2("cc", "LayerTreeImpl::UpdateDrawProperties::Occlusion",
 601                  "IsActive", IsActiveTree(), "SourceFrameNumber",
 602                  source_frame_number_);
 603     OcclusionTracker<LayerImpl> occlusion_tracker(
 604         root_layer()->render_surface()->content_rect());
 605     occlusion_tracker.set_minimum_tracking_size(
 606         settings().minimum_occlusion_tracking_size);
 607
 608     // LayerIterator is used here instead of CallFunctionForSubtree to only
 609     // UpdateTilePriorities on layers that will be visible (and thus have valid
 610     // draw properties) and not because any ordering is required.
 611     auto end = LayerIterator<LayerImpl>::End(&render_surface_layer_list_);
 612     for (auto it = LayerIterator<LayerImpl>::Begin(&render_surface_layer_list_);
 613          it != end; ++it) {
 614       occlusion_tracker.EnterLayer(it);
 615
 616       // There are very few render targets so this should be cheap to do for
 617       // each layer instead of something more complicated.
 618       bool inside_replica = false;
 619       LayerImpl* layer = it->render_target();
 620       while (layer && !inside_replica) {
 621         if (layer->render_target()->has_replica())
 622           inside_replica = true;
 623         layer = layer->render_target()->parent();
 624       }
 625
 626       // Don't use occlusion if a layer will appear in a replica, since the
 627       // tile raster code does not know how to look for the replica and would
 628       // consider it occluded even though the replica is visible.
 629       // Since occlusion is only used for browser compositor (i.e.
 630       // use_occlusion_for_tile_prioritization) and it won't use replicas,
 631       // this should matter not.
 632
 633       if (it.represents_itself()) {
 634         Occlusion occlusion =
 635             inside_replica ? Occlusion()
 636                            : occlusion_tracker.GetCurrentOcclusionForLayer(
 637                                  it->draw_transform());
 638         it->draw_properties().occlusion_in_content_space = occlusion;
 639       }
 640
 641       if (it.represents_contributing_render_surface()) {
 642         // Surfaces aren't used by the tile raster code, so they can have
 643         // occlusion regardless of replicas.
 644         Occlusion occlusion =
 645             occlusion_tracker.GetCurrentOcclusionForContributingSurface(
 646                 it->render_surface()->draw_transform());
 647         it->render_surface()->set_occlusion_in_content_space(occlusion);
 648         // Masks are used to draw the contributing surface, so should have
 649         // the same occlusion as the surface (nothing inside the surface
 650         // occludes them).
 651         if (LayerImpl* mask = it->mask_layer()) {
 652           Occlusion mask_occlusion =
 653               inside_replica
 654                   ? Occlusion()
 655                   : occlusion_tracker.GetCurrentOcclusionForContributingSurface(
 656                         it->render_surface()->draw_transform() *
 657                         it->draw_transform());
 658           mask->draw_properties().occlusion_in_content_space = mask_occlusion;
 659         }
 660         if (LayerImpl* replica = it->replica_layer()) {
 661           if (LayerImpl* mask = replica->mask_layer())
 662             mask->draw_properties().occlusion_in_content_space = Occlusion();
 663         }
 664       }
 665
 666       occlusion_tracker.LeaveLayer(it);
 667     }
 668
 669     unoccluded_screen_space_region_ =
 670         occlusion_tracker.ComputeVisibleRegionInScreen();
 671   }
 672
 673   // It'd be ideal if this could be done earlier, but when the raster source
 674   // is updated from the main thread during push properties, update draw
 675   // properties has not occurred yet and so it's not clear whether or not the
 676   // layer can or cannot use lcd text.  So, this is the cleanup pass to
 677   // determine if the raster source needs to be replaced with a non-lcd
 678   // raster source due to draw properties.
 679   if (update_lcd_text) {
 680     // TODO(enne): Make LTHI::sync_tree return this value.
 681     LayerTreeImpl* sync_tree =
 682         layer_tree_host_impl_->proxy()->CommitToActiveTree()
 683             ? layer_tree_host_impl_->active_tree()
 684             : layer_tree_host_impl_->pending_tree();
 685     // If this is not the sync tree, then it is not safe to update lcd text
 686     // as it causes invalidations and the tiles may be in use.
 687     DCHECK_EQ(this, sync_tree);
 688     for (const auto& layer : picture_layers_)
 689       layer->UpdateCanUseLCDTextAfterCommit();
 690   }
 691
 692   {
 693     TRACE_EVENT_BEGIN2("cc", "LayerTreeImpl::UpdateDrawProperties::UpdateTiles",
 694                        "IsActive", IsActiveTree(), "SourceFrameNumber",
 695                        source_frame_number_);
 696     const bool resourceless_software_draw =
 697         (layer_tree_host_impl_->GetDrawMode() ==
 698          DRAW_MODE_RESOURCELESS_SOFTWARE);
 699     size_t layers_updated_count = 0;
 700     bool tile_priorities_updated = false;
 701     for (PictureLayerImpl* layer : picture_layers_) {
 702       if (!layer->IsDrawnRenderSurfaceLayerListMember())
 703         continue;
 704       ++layers_updated_count;
 705       tile_priorities_updated |= layer->UpdateTiles(resourceless_software_draw);
 706     }
 707
 708     if (tile_priorities_updated)
 709       DidModifyTilePriorities();
 710
 711     TRACE_EVENT_END1("cc", "LayerTreeImpl::UpdateTilePriorities",
 712                      "layers_updated_count", layers_updated_count);
 713   }
 714
 715   DCHECK(!needs_update_draw_properties_) <<
 716       "CalcDrawProperties should not set_needs_update_draw_properties()";
 717   return true;
 718 }
 719
 720 const LayerImplList& LayerTreeImpl::RenderSurfaceLayerList() const {
 721   // If this assert triggers, then the list is dirty.
 722   DCHECK(!needs_update_draw_properties_);
 723   return render_surface_layer_list_;
 724 }
 725
 726 const Region& LayerTreeImpl::UnoccludedScreenSpaceRegion() const {
 727   // If this assert triggers, then the render_surface_layer_list_ is dirty, so
 728   // the unoccluded_screen_space_region_ is not valid anymore.
 729   DCHECK(!needs_update_draw_properties_);
 730   return unoccluded_screen_space_region_;
 731 }
 732
 733 gfx::Size LayerTreeImpl::ScrollableSize() const {
 734   LayerImpl* root_scroll_layer = OuterViewportScrollLayer()
 735                                      ? OuterViewportScrollLayer()
 736                                      : InnerViewportScrollLayer();
 737   if (!root_scroll_layer || root_scroll_layer->children().empty())
 738     return gfx::Size();
 739   return root_scroll_layer->children()[0]->bounds();
 740 }
 741
 742 LayerImpl* LayerTreeImpl::LayerById(int id) {
 743   LayerIdMap::iterator iter = layer_id_map_.find(id);
 744   return iter != layer_id_map_.end() ? iter->second : NULL;
 745 }
 746
 747 void LayerTreeImpl::RegisterLayer(LayerImpl* layer) {
 748   DCHECK(!LayerById(layer->id()));
 749   layer_id_map_[layer->id()] = layer;
 750 }
 751
 752 void LayerTreeImpl::UnregisterLayer(LayerImpl* layer) {
 753   DCHECK(LayerById(layer->id()));
 754   layer_id_map_.erase(layer->id());
 755 }
 756
 757 size_t LayerTreeImpl::NumLayers() {
 758   return layer_id_map_.size();
 759 }
 760
 761 void LayerTreeImpl::PushPersistedState(LayerTreeImpl* pending_tree) {
 762   pending_tree->SetCurrentlyScrollingLayer(
 763       LayerTreeHostCommon::FindLayerInSubtree(pending_tree->root_layer(),
 764           currently_scrolling_layer_ ? currently_scrolling_layer_->id() : 0));
 765 }
 766
 767 void LayerTreeImpl::DidBecomeActive() {
 768   if (next_activation_forces_redraw_) {
 769     layer_tree_host_impl_->SetFullRootLayerDamage();
 770     next_activation_forces_redraw_ = false;
 771   }
 772
 773   if (scrolling_layer_id_from_previous_tree_) {
 774     currently_scrolling_layer_ = LayerTreeHostCommon::FindLayerInSubtree(
 775         root_layer(), scrolling_layer_id_from_previous_tree_);
 776   }
 777
 778   // Always reset this flag on activation, as we would only have activated
 779   // if we were in a good state.
 780   layer_tree_host_impl_->ResetRequiresHighResToDraw();
 781
 782   if (root_layer()) {
 783     LayerTreeHostCommon::CallFunctionForSubtree(
 784         root_layer(), [](LayerImpl* layer) { layer->DidBecomeActive(); });
 785   }
 786
 787   devtools_instrumentation::DidActivateLayerTree(layer_tree_host_impl_->id(),
 788                                                  source_frame_number_);
 789 }
 790
 791 bool LayerTreeImpl::ContentsTexturesPurged() const {
 792   return contents_textures_purged_;
 793 }
 794
 795 void LayerTreeImpl::SetContentsTexturesPurged() {
 796   if (contents_textures_purged_)
 797     return;
 798   contents_textures_purged_ = true;
 799   layer_tree_host_impl_->OnCanDrawStateChangedForTree();
 800 }
 801
 802 void LayerTreeImpl::ResetContentsTexturesPurged() {
 803   if (!contents_textures_purged_)
 804     return;
 805   contents_textures_purged_ = false;
 806   layer_tree_host_impl_->OnCanDrawStateChangedForTree();
 807 }
 808
 809 bool LayerTreeImpl::RequiresHighResToDraw() const {
 810   return layer_tree_host_impl_->RequiresHighResToDraw();
 811 }
 812
 813 bool LayerTreeImpl::ViewportSizeInvalid() const {
 814   return viewport_size_invalid_;
 815 }
 816
 817 void LayerTreeImpl::SetViewportSizeInvalid() {
 818   viewport_size_invalid_ = true;
 819   layer_tree_host_impl_->OnCanDrawStateChangedForTree();
 820 }
 821
 822 void LayerTreeImpl::ResetViewportSizeInvalid() {
 823   viewport_size_invalid_ = false;
 824   layer_tree_host_impl_->OnCanDrawStateChangedForTree();
 825 }
 826
 827 Proxy* LayerTreeImpl::proxy() const {
 828   return layer_tree_host_impl_->proxy();
 829 }
 830
 831 const LayerTreeSettings& LayerTreeImpl::settings() const {
 832   return layer_tree_host_impl_->settings();
 833 }
 834
 835 const LayerTreeDebugState& LayerTreeImpl::debug_state() const {
 836   return layer_tree_host_impl_->debug_state();
 837 }
 838
 839 const RendererCapabilitiesImpl& LayerTreeImpl::GetRendererCapabilities() const {
 840   return layer_tree_host_impl_->GetRendererCapabilities();
 841 }
 842
 843 ContextProvider* LayerTreeImpl::context_provider() const {
 844   return output_surface()->context_provider();
 845 }
 846
 847 OutputSurface* LayerTreeImpl::output_surface() const {
 848   return layer_tree_host_impl_->output_surface();
 849 }
 850
 851 ResourceProvider* LayerTreeImpl::resource_provider() const {
 852   return layer_tree_host_impl_->resource_provider();
 853 }
 854
 855 TileManager* LayerTreeImpl::tile_manager() const {
 856   return layer_tree_host_impl_->tile_manager();
 857 }
 858
 859 FrameRateCounter* LayerTreeImpl::frame_rate_counter() const {
 860   return layer_tree_host_impl_->fps_counter();
 861 }
 862
 863 PaintTimeCounter* LayerTreeImpl::paint_time_counter() const {
 864   return layer_tree_host_impl_->paint_time_counter();
 865 }
 866
 867 MemoryHistory* LayerTreeImpl::memory_history() const {
 868   return layer_tree_host_impl_->memory_history();
 869 }
 870
 871 gfx::Size LayerTreeImpl::device_viewport_size() const {
 872   return layer_tree_host_impl_->device_viewport_size();
 873 }
 874
 875 float LayerTreeImpl::device_scale_factor() const {
 876   return layer_tree_host_impl_->device_scale_factor();
 877 }
 878
 879 DebugRectHistory* LayerTreeImpl::debug_rect_history() const {
 880   return layer_tree_host_impl_->debug_rect_history();
 881 }
 882
 883 bool LayerTreeImpl::IsActiveTree() const {
 884   return layer_tree_host_impl_->active_tree() == this;
 885 }
 886
 887 bool LayerTreeImpl::IsPendingTree() const {
 888   return layer_tree_host_impl_->pending_tree() == this;
 889 }
 890
 891 bool LayerTreeImpl::IsRecycleTree() const {
 892   return layer_tree_host_impl_->recycle_tree() == this;
 893 }
 894
 895 bool LayerTreeImpl::IsSyncTree() const {
 896   return layer_tree_host_impl_->sync_tree() == this;
 897 }
 898
 899 LayerImpl* LayerTreeImpl::FindActiveTreeLayerById(int id) {
 900   LayerTreeImpl* tree = layer_tree_host_impl_->active_tree();
 901   if (!tree)
 902     return NULL;
 903   return tree->LayerById(id);
 904 }
 905
 906 LayerImpl* LayerTreeImpl::FindPendingTreeLayerById(int id) {
 907   LayerTreeImpl* tree = layer_tree_host_impl_->pending_tree();
 908   if (!tree)
 909     return NULL;
 910   return tree->LayerById(id);
 911 }
 912
 913 bool LayerTreeImpl::PinchGestureActive() const {
 914   return layer_tree_host_impl_->pinch_gesture_active();
 915 }
 916
 917 BeginFrameArgs LayerTreeImpl::CurrentBeginFrameArgs() const {
 918   return layer_tree_host_impl_->CurrentBeginFrameArgs();
 919 }
 920
 921 base::TimeDelta LayerTreeImpl::begin_impl_frame_interval() const {
 922   return layer_tree_host_impl_->begin_impl_frame_interval();
 923 }
 924
 925 void LayerTreeImpl::SetNeedsCommit() {
 926   layer_tree_host_impl_->SetNeedsCommit();
 927 }
 928
 929 gfx::Rect LayerTreeImpl::DeviceViewport() const {
 930   return layer_tree_host_impl_->DeviceViewport();
 931 }
 932
 933 gfx::Size LayerTreeImpl::DrawViewportSize() const {
 934   return layer_tree_host_impl_->DrawViewportSize();
 935 }
 936
 937 const gfx::Rect LayerTreeImpl::ViewportRectForTilePriority() const {
 938   return layer_tree_host_impl_->ViewportRectForTilePriority();
 939 }
 940
 941 scoped_ptr<ScrollbarAnimationController>
 942 LayerTreeImpl::CreateScrollbarAnimationController(LayerImpl* scrolling_layer) {
 943   DCHECK(settings().scrollbar_fade_delay_ms);
 944   DCHECK(settings().scrollbar_fade_duration_ms);
 945   base::TimeDelta delay =
 946       base::TimeDelta::FromMilliseconds(settings().scrollbar_fade_delay_ms);
 947   base::TimeDelta resize_delay = base::TimeDelta::FromMilliseconds(
 948       settings().scrollbar_fade_resize_delay_ms);
 949   base::TimeDelta duration =
 950       base::TimeDelta::FromMilliseconds(settings().scrollbar_fade_duration_ms);
 951   switch (settings().scrollbar_animator) {
 952     case LayerTreeSettings::LINEAR_FADE: {
 953       return ScrollbarAnimationControllerLinearFade::Create(
 954           scrolling_layer,
 955           layer_tree_host_impl_,
 956           delay,
 957           resize_delay,
 958           duration);
 959     }
 960     case LayerTreeSettings::THINNING: {
 961       return ScrollbarAnimationControllerThinning::Create(scrolling_layer,
 962                                                           layer_tree_host_impl_,
 963                                                           delay,
 964                                                           resize_delay,
 965                                                           duration);
 966     }
 967     case LayerTreeSettings::NO_ANIMATOR:
 968       NOTREACHED();
 969       break;
 970   }
 971   return nullptr;
 972 }
 973
 974 void LayerTreeImpl::DidAnimateScrollOffset() {
 975   layer_tree_host_impl_->DidAnimateScrollOffset();
 976 }
 977
 978 bool LayerTreeImpl::use_gpu_rasterization() const {
 979   return layer_tree_host_impl_->use_gpu_rasterization();
 980 }
 981
 982 GpuRasterizationStatus LayerTreeImpl::GetGpuRasterizationStatus() const {
 983   return layer_tree_host_impl_->gpu_rasterization_status();
 984 }
 985
 986 bool LayerTreeImpl::create_low_res_tiling() const {
 987   return layer_tree_host_impl_->create_low_res_tiling();
 988 }
 989
 990 void LayerTreeImpl::SetNeedsRedraw() {
 991   layer_tree_host_impl_->SetNeedsRedraw();
 992 }
 993
 994 AnimationRegistrar* LayerTreeImpl::GetAnimationRegistrar() const {
 995   return layer_tree_host_impl_->animation_registrar();
 996 }
 997
 998 void LayerTreeImpl::GetAllTilesAndPrioritiesForTracing(
 999     std::map<const Tile*, TilePriority>* tile_map) const {
1000   typedef LayerIterator<LayerImpl> LayerIteratorType;
1001   LayerIteratorType end = LayerIteratorType::End(&render_surface_layer_list_);
1002   for (LayerIteratorType it =
1003            LayerIteratorType::Begin(&render_surface_layer_list_);
1004        it != end;
1005        ++it) {
1006     if (!it.represents_itself())
1007       continue;
1008     LayerImpl* layer_impl = *it;
1009     layer_impl->GetAllTilesAndPrioritiesForTracing(tile_map);
1010   }
1011 }
1012
1013 void LayerTreeImpl::AsValueInto(base::trace_event::TracedValue* state) const {
1014   TracedValue::MakeDictIntoImplicitSnapshot(state, "cc::LayerTreeImpl", this);
1015   state->SetInteger("source_frame_number", source_frame_number_);
1016
1017   state->BeginDictionary("root_layer");
1018   root_layer_->AsValueInto(state);
1019   state->EndDictionary();
1020
1021   state->BeginArray("render_surface_layer_list");
1022   typedef LayerIterator<LayerImpl> LayerIteratorType;
1023   LayerIteratorType end = LayerIteratorType::End(&render_surface_layer_list_);
1024   for (LayerIteratorType it = LayerIteratorType::Begin(
1025            &render_surface_layer_list_); it != end; ++it) {
1026     if (!it.represents_itself())
1027       continue;
1028     TracedValue::AppendIDRef(*it, state);
1029   }
1030   state->EndArray();
1031
1032   state->BeginArray("swap_promise_trace_ids");
1033   for (size_t i = 0; i < swap_promise_list_.size(); i++)
1034     state->AppendDouble(swap_promise_list_[i]->TraceId());
1035   state->EndArray();
1036 }
1037
1038 void LayerTreeImpl::SetRootLayerScrollOffsetDelegate(
1039     LayerScrollOffsetDelegate* root_layer_scroll_offset_delegate) {
1040   if (root_layer_scroll_offset_delegate_ == root_layer_scroll_offset_delegate)
1041     return;
1042
1043   if (!root_layer_scroll_offset_delegate) {
1044     // Make sure we remove the proxies from their layers before
1045     // releasing them.
1046     if (InnerViewportScrollLayer())
1047       InnerViewportScrollLayer()->SetScrollOffsetDelegate(NULL);
1048     if (OuterViewportScrollLayer())
1049       OuterViewportScrollLayer()->SetScrollOffsetDelegate(NULL);
1050     inner_viewport_scroll_delegate_proxy_ = nullptr;
1051     outer_viewport_scroll_delegate_proxy_ = nullptr;
1052   }
1053
1054   root_layer_scroll_offset_delegate_ = root_layer_scroll_offset_delegate;
1055
1056   if (root_layer_scroll_offset_delegate_) {
1057     root_layer_scroll_offset_delegate_->UpdateRootLayerState(
1058         TotalScrollOffset(), TotalMaxScrollOffset(), ScrollableSize(),
1059         current_page_scale_factor(), min_page_scale_factor(),
1060         max_page_scale_factor());
1061
1062     if (inner_viewport_scroll_layer_) {
1063       inner_viewport_scroll_delegate_proxy_ = make_scoped_ptr(
1064           new LayerScrollOffsetDelegateProxy(InnerViewportScrollLayer(),
1065                                              root_layer_scroll_offset_delegate_,
1066                                              this));
1067       inner_viewport_scroll_layer_->SetScrollOffsetDelegate(
1068           inner_viewport_scroll_delegate_proxy_.get());
1069     }
1070
1071     if (outer_viewport_scroll_layer_) {
1072       outer_viewport_scroll_delegate_proxy_ = make_scoped_ptr(
1073           new LayerScrollOffsetDelegateProxy(OuterViewportScrollLayer(),
1074                                              root_layer_scroll_offset_delegate_,
1075                                              this));
1076       outer_viewport_scroll_layer_->SetScrollOffsetDelegate(
1077           outer_viewport_scroll_delegate_proxy_.get());
1078     }
1079
1080     if (inner_viewport_scroll_layer_)
1081       inner_viewport_scroll_layer_->RefreshFromScrollDelegate();
1082     if (outer_viewport_scroll_layer_)
1083       outer_viewport_scroll_layer_->RefreshFromScrollDelegate();
1084
1085     if (inner_viewport_scroll_layer_)
1086       UpdateScrollOffsetDelegate();
1087   }
1088 }
1089
1090 void LayerTreeImpl::OnRootLayerDelegatedScrollOffsetChanged() {
1091   DCHECK(root_layer_scroll_offset_delegate_);
1092   if (inner_viewport_scroll_layer_) {
1093     inner_viewport_scroll_layer_->RefreshFromScrollDelegate();
1094   }
1095   if (outer_viewport_scroll_layer_) {
1096     outer_viewport_scroll_layer_->RefreshFromScrollDelegate();
1097   }
1098 }
1099
1100 void LayerTreeImpl::UpdateScrollOffsetDelegate() {
1101   DCHECK(InnerViewportScrollLayer());
1102   DCHECK(!OuterViewportScrollLayer() || outer_viewport_scroll_delegate_proxy_);
1103   DCHECK(root_layer_scroll_offset_delegate_);
1104
1105   gfx::ScrollOffset offset =
1106       inner_viewport_scroll_delegate_proxy_->last_set_scroll_offset();
1107
1108   if (OuterViewportScrollLayer())
1109     offset += outer_viewport_scroll_delegate_proxy_->last_set_scroll_offset();
1110
1111   root_layer_scroll_offset_delegate_->UpdateRootLayerState(
1112       offset, TotalMaxScrollOffset(), ScrollableSize(),
1113       current_page_scale_factor(), min_page_scale_factor(),
1114       max_page_scale_factor());
1115 }
1116
1117 gfx::ScrollOffset LayerTreeImpl::GetDelegatedScrollOffset(LayerImpl* layer) {
1118   DCHECK(root_layer_scroll_offset_delegate_);
1119   DCHECK(InnerViewportScrollLayer());
1120   if (layer == InnerViewportScrollLayer() && !OuterViewportScrollLayer())
1121     return root_layer_scroll_offset_delegate_->GetTotalScrollOffset();
1122
1123   // If we get here, we have both inner/outer viewports, and need to distribute
1124   // the scroll offset between them.
1125   DCHECK(inner_viewport_scroll_delegate_proxy_);
1126   DCHECK(outer_viewport_scroll_delegate_proxy_);
1127   gfx::ScrollOffset inner_viewport_offset =
1128       inner_viewport_scroll_delegate_proxy_->last_set_scroll_offset();
1129   gfx::ScrollOffset outer_viewport_offset =
1130       outer_viewport_scroll_delegate_proxy_->last_set_scroll_offset();
1131
1132   // It may be nothing has changed.
1133   gfx::ScrollOffset delegate_offset =
1134       root_layer_scroll_offset_delegate_->GetTotalScrollOffset();
1135   if (inner_viewport_offset + outer_viewport_offset == delegate_offset) {
1136     if (layer == InnerViewportScrollLayer())
1137       return inner_viewport_offset;
1138     else
1139       return outer_viewport_offset;
1140   }
1141
1142   gfx::ScrollOffset max_outer_viewport_scroll_offset =
1143       OuterViewportScrollLayer()->MaxScrollOffset();
1144
1145   outer_viewport_offset = delegate_offset - inner_viewport_offset;
1146   outer_viewport_offset.SetToMin(max_outer_viewport_scroll_offset);
1147   outer_viewport_offset.SetToMax(gfx::ScrollOffset());
1148
1149   if (layer == OuterViewportScrollLayer())
1150     return outer_viewport_offset;
1151
1152   inner_viewport_offset = delegate_offset - outer_viewport_offset;
1153
1154   return inner_viewport_offset;
1155 }
1156
1157 void LayerTreeImpl::QueueSwapPromise(scoped_ptr<SwapPromise> swap_promise) {
1158   DCHECK(swap_promise);
1159   swap_promise_list_.push_back(swap_promise.Pass());
1160 }
1161
1162 void LayerTreeImpl::PassSwapPromises(
1163     ScopedPtrVector<SwapPromise>* new_swap_promise) {
1164   swap_promise_list_.insert_and_take(swap_promise_list_.end(),
1165                                      new_swap_promise);
1166   new_swap_promise->clear();
1167 }
1168
1169 void LayerTreeImpl::FinishSwapPromises(CompositorFrameMetadata* metadata) {
1170   for (size_t i = 0; i < swap_promise_list_.size(); i++)
1171     swap_promise_list_[i]->DidSwap(metadata);
1172   swap_promise_list_.clear();
1173 }
1174
1175 void LayerTreeImpl::BreakSwapPromises(SwapPromise::DidNotSwapReason reason) {
1176   for (size_t i = 0; i < swap_promise_list_.size(); i++)
1177     swap_promise_list_[i]->DidNotSwap(reason);
1178   swap_promise_list_.clear();
1179 }
1180
1181 void LayerTreeImpl::DidModifyTilePriorities() {
1182   layer_tree_host_impl_->DidModifyTilePriorities();
1183 }
1184
1185 void LayerTreeImpl::set_ui_resource_request_queue(
1186     const UIResourceRequestQueue& queue) {
1187   ui_resource_request_queue_ = queue;
1188 }
1189
1190 ResourceProvider::ResourceId LayerTreeImpl::ResourceIdForUIResource(
1191     UIResourceId uid) const {
1192   return layer_tree_host_impl_->ResourceIdForUIResource(uid);
1193 }
1194
1195 bool LayerTreeImpl::IsUIResourceOpaque(UIResourceId uid) const {
1196   return layer_tree_host_impl_->IsUIResourceOpaque(uid);
1197 }
1198
1199 void LayerTreeImpl::ProcessUIResourceRequestQueue() {
1200   for (const auto& req : ui_resource_request_queue_) {
1201     switch (req.GetType()) {
1202       case UIResourceRequest::UI_RESOURCE_CREATE:
1203         layer_tree_host_impl_->CreateUIResource(req.GetId(), req.GetBitmap());
1204         break;
1205       case UIResourceRequest::UI_RESOURCE_DELETE:
1206         layer_tree_host_impl_->DeleteUIResource(req.GetId());
1207         break;
1208       case UIResourceRequest::UI_RESOURCE_INVALID_REQUEST:
1209         NOTREACHED();
1210         break;
1211     }
1212   }
1213   ui_resource_request_queue_.clear();
1214
1215   // If all UI resource evictions were not recreated by processing this queue,
1216   // then another commit is required.
1217   if (layer_tree_host_impl_->EvictedUIResourcesExist())
1218     layer_tree_host_impl_->SetNeedsCommit();
1219 }
1220
1221 void LayerTreeImpl::RegisterPictureLayerImpl(PictureLayerImpl* layer) {
1222   DCHECK(std::find(picture_layers_.begin(), picture_layers_.end(), layer) ==
1223          picture_layers_.end());
1224   picture_layers_.push_back(layer);
1225 }
1226
1227 void LayerTreeImpl::UnregisterPictureLayerImpl(PictureLayerImpl* layer) {
1228   std::vector<PictureLayerImpl*>::iterator it =
1229       std::find(picture_layers_.begin(), picture_layers_.end(), layer);
1230   DCHECK(it != picture_layers_.end());
1231   picture_layers_.erase(it);
1232 }
1233
1234 void LayerTreeImpl::AddLayerWithCopyOutputRequest(LayerImpl* layer) {
1235   // Only the active tree needs to know about layers with copy requests, as
1236   // they are aborted if not serviced during draw.
1237   DCHECK(IsActiveTree());
1238
1239   // DCHECK(std::find(layers_with_copy_output_request_.begin(),
1240   //                 layers_with_copy_output_request_.end(),
1241   //                 layer) == layers_with_copy_output_request_.end());
1242   // TODO(danakj): Remove this once crash is found crbug.com/309777
1243   for (size_t i = 0; i < layers_with_copy_output_request_.size(); ++i) {
1244     CHECK(layers_with_copy_output_request_[i] != layer)
1245         << i << " of " << layers_with_copy_output_request_.size();
1246   }
1247   layers_with_copy_output_request_.push_back(layer);
1248 }
1249
1250 void LayerTreeImpl::RemoveLayerWithCopyOutputRequest(LayerImpl* layer) {
1251   // Only the active tree needs to know about layers with copy requests, as
1252   // they are aborted if not serviced during draw.
1253   DCHECK(IsActiveTree());
1254
1255   std::vector<LayerImpl*>::iterator it = std::find(
1256       layers_with_copy_output_request_.begin(),
1257       layers_with_copy_output_request_.end(),
1258       layer);
1259   DCHECK(it != layers_with_copy_output_request_.end());
1260   layers_with_copy_output_request_.erase(it);
1261
1262   // TODO(danakj): Remove this once crash is found crbug.com/309777
1263   for (size_t i = 0; i < layers_with_copy_output_request_.size(); ++i) {
1264     CHECK(layers_with_copy_output_request_[i] != layer)
1265         << i << " of " << layers_with_copy_output_request_.size();
1266   }
1267 }
1268
1269 const std::vector<LayerImpl*>& LayerTreeImpl::LayersWithCopyOutputRequest()
1270     const {
1271   // Only the active tree needs to know about layers with copy requests, as
1272   // they are aborted if not serviced during draw.
1273   DCHECK(IsActiveTree());
1274
1275   return layers_with_copy_output_request_;
1276 }
1277
1278 template <typename LayerType>
1279 static inline bool LayerClipsSubtree(LayerType* layer) {
1280   return layer->masks_to_bounds() || layer->mask_layer();
1281 }
1282
1283 static bool PointHitsRect(
1284     const gfx::PointF& screen_space_point,
1285     const gfx::Transform& local_space_to_screen_space_transform,
1286     const gfx::RectF& local_space_rect,
1287     float* distance_to_camera) {
1288   // If the transform is not invertible, then assume that this point doesn't hit
1289   // this rect.
1290   gfx::Transform inverse_local_space_to_screen_space(
1291       gfx::Transform::kSkipInitialization);
1292   if (!local_space_to_screen_space_transform.GetInverse(
1293           &inverse_local_space_to_screen_space))
1294     return false;
1295
1296   // Transform the hit test point from screen space to the local space of the
1297   // given rect.
1298   bool clipped = false;
1299   gfx::Point3F planar_point = MathUtil::ProjectPoint3D(
1300       inverse_local_space_to_screen_space, screen_space_point, &clipped);
1301   gfx::PointF hit_test_point_in_local_space =
1302       gfx::PointF(planar_point.x(), planar_point.y());
1303
1304   // If ProjectPoint could not project to a valid value, then we assume that
1305   // this point doesn't hit this rect.
1306   if (clipped)
1307     return false;
1308
1309   if (!local_space_rect.Contains(hit_test_point_in_local_space))
1310     return false;
1311
1312   if (distance_to_camera) {
1313     // To compute the distance to the camera, we have to take the planar point
1314     // and pull it back to world space and compute the displacement along the
1315     // z-axis.
1316     gfx::Point3F planar_point_in_screen_space(planar_point);
1317     local_space_to_screen_space_transform.TransformPoint(
1318         &planar_point_in_screen_space);
1319     *distance_to_camera = planar_point_in_screen_space.z();
1320   }
1321
1322   return true;
1323 }
1324
1325 static bool PointHitsRegion(const gfx::PointF& screen_space_point,
1326                             const gfx::Transform& screen_space_transform,
1327                             const Region& layer_space_region,
1328                             float layer_content_scale_x,
1329                             float layer_content_scale_y) {
1330   // If the transform is not invertible, then assume that this point doesn't hit
1331   // this region.
1332   gfx::Transform inverse_screen_space_transform(
1333       gfx::Transform::kSkipInitialization);
1334   if (!screen_space_transform.GetInverse(&inverse_screen_space_transform))
1335     return false;
1336
1337   // Transform the hit test point from screen space to the local space of the
1338   // given region.
1339   bool clipped = false;
1340   gfx::PointF hit_test_point_in_content_space = MathUtil::ProjectPoint(
1341       inverse_screen_space_transform, screen_space_point, &clipped);
1342   gfx::PointF hit_test_point_in_layer_space =
1343       gfx::ScalePoint(hit_test_point_in_content_space,
1344                       1.f / layer_content_scale_x,
1345                       1.f / layer_content_scale_y);
1346
1347   // If ProjectPoint could not project to a valid value, then we assume that
1348   // this point doesn't hit this region.
1349   if (clipped)
1350     return false;
1351
1352   return layer_space_region.Contains(
1353       gfx::ToRoundedPoint(hit_test_point_in_layer_space));
1354 }
1355
1356 static const LayerImpl* GetNextClippingLayer(const LayerImpl* layer) {
1357   if (layer->scroll_parent())
1358     return layer->scroll_parent();
1359   if (layer->clip_parent())
1360     return layer->clip_parent();
1361   return layer->parent();
1362 }
1363
1364 static bool PointIsClippedBySurfaceOrClipRect(
1365     const gfx::PointF& screen_space_point,
1366     const LayerImpl* layer) {
1367   // Walk up the layer tree and hit-test any render_surfaces and any layer
1368   // clip rects that are active.
1369   for (; layer; layer = GetNextClippingLayer(layer)) {
1370     if (layer->render_surface() &&
1371         !PointHitsRect(screen_space_point,
1372                        layer->render_surface()->screen_space_transform(),
1373                        layer->render_surface()->content_rect(),
1374                        NULL))
1375       return true;
1376
1377     if (LayerClipsSubtree(layer) &&
1378         !PointHitsRect(screen_space_point,
1379                        layer->screen_space_transform(),
1380                        gfx::Rect(layer->content_bounds()),
1381                        NULL))
1382       return true;
1383   }
1384
1385   // If we have finished walking all ancestors without having already exited,
1386   // then the point is not clipped by any ancestors.
1387   return false;
1388 }
1389
1390 static bool PointHitsLayer(const LayerImpl* layer,
1391                            const gfx::PointF& screen_space_point,
1392                            float* distance_to_intersection) {
1393   gfx::RectF content_rect(layer->content_bounds());
1394   if (!PointHitsRect(screen_space_point,
1395                      layer->screen_space_transform(),
1396                      content_rect,
1397                      distance_to_intersection))
1398     return false;
1399
1400   // At this point, we think the point does hit the layer, but we need to walk
1401   // up the parents to ensure that the layer was not clipped in such a way
1402   // that the hit point actually should not hit the layer.
1403   if (PointIsClippedBySurfaceOrClipRect(screen_space_point, layer))
1404     return false;
1405
1406   // Skip the HUD layer.
1407   if (layer == layer->layer_tree_impl()->hud_layer())
1408     return false;
1409
1410   return true;
1411 }
1412
1413 struct FindClosestMatchingLayerDataForRecursion {
1414   FindClosestMatchingLayerDataForRecursion()
1415       : closest_match(NULL),
1416         closest_distance(-std::numeric_limits<float>::infinity()) {}
1417   LayerImpl* closest_match;
1418   // Note that the positive z-axis points towards the camera, so bigger means
1419   // closer in this case, counterintuitively.
1420   float closest_distance;
1421 };
1422
1423 template <typename Functor>
1424 static void FindClosestMatchingLayer(
1425     const gfx::PointF& screen_space_point,
1426     LayerImpl* layer,
1427     const Functor& func,
1428     FindClosestMatchingLayerDataForRecursion* data_for_recursion) {
1429   for (int i = layer->children().size() - 1; i >= 0; --i) {
1430     FindClosestMatchingLayer(
1431         screen_space_point, layer->children()[i], func, data_for_recursion);
1432   }
1433
1434   float distance_to_intersection = 0.f;
1435   if (func(layer) &&
1436       PointHitsLayer(layer, screen_space_point, &distance_to_intersection) &&
1437       ((!data_for_recursion->closest_match ||
1438         distance_to_intersection > data_for_recursion->closest_distance))) {
1439     data_for_recursion->closest_distance = distance_to_intersection;
1440     data_for_recursion->closest_match = layer;
1441   }
1442 }
1443
1444 static bool ScrollsAnyDrawnRenderSurfaceLayerListMember(LayerImpl* layer) {
1445   if (!layer->scrollable())
1446     return false;
1447   if (layer->draw_properties().layer_or_descendant_is_drawn)
1448     return true;
1449
1450   if (!layer->scroll_children())
1451     return false;
1452   for (std::set<LayerImpl*>::const_iterator it =
1453            layer->scroll_children()->begin();
1454        it != layer->scroll_children()->end();
1455        ++it) {
1456     if ((*it)->draw_properties().layer_or_descendant_is_drawn)
1457       return true;
1458   }
1459   return false;
1460 }
1461
1462 struct FindScrollingLayerFunctor {
1463   bool operator()(LayerImpl* layer) const {
1464     return ScrollsAnyDrawnRenderSurfaceLayerListMember(layer);
1465   }
1466 };
1467
1468 LayerImpl* LayerTreeImpl::FindFirstScrollingLayerThatIsHitByPoint(
1469     const gfx::PointF& screen_space_point) {
1470   FindClosestMatchingLayerDataForRecursion data_for_recursion;
1471   FindClosestMatchingLayer(screen_space_point,
1472                            root_layer(),
1473                            FindScrollingLayerFunctor(),
1474                            &data_for_recursion);
1475   return data_for_recursion.closest_match;
1476 }
1477
1478 struct HitTestVisibleScrollableOrTouchableFunctor {
1479   bool operator()(LayerImpl* layer) const {
1480     return layer->IsDrawnRenderSurfaceLayerListMember() ||
1481            ScrollsAnyDrawnRenderSurfaceLayerListMember(layer) ||
1482            !layer->touch_event_handler_region().IsEmpty() ||
1483            layer->have_wheel_event_handlers();
1484   }
1485 };
1486
1487 LayerImpl* LayerTreeImpl::FindLayerThatIsHitByPoint(
1488     const gfx::PointF& screen_space_point) {
1489   if (!root_layer())
1490     return NULL;
1491   bool update_lcd_text = false;
1492   if (!UpdateDrawProperties(update_lcd_text))
1493     return NULL;
1494   FindClosestMatchingLayerDataForRecursion data_for_recursion;
1495   FindClosestMatchingLayer(screen_space_point,
1496                            root_layer(),
1497                            HitTestVisibleScrollableOrTouchableFunctor(),
1498                            &data_for_recursion);
1499   return data_for_recursion.closest_match;
1500 }
1501
1502 static bool LayerHasTouchEventHandlersAt(const gfx::PointF& screen_space_point,
1503                                          LayerImpl* layer_impl) {
1504   if (layer_impl->touch_event_handler_region().IsEmpty())
1505     return false;
1506
1507   if (!PointHitsRegion(screen_space_point,
1508                        layer_impl->screen_space_transform(),
1509                        layer_impl->touch_event_handler_region(),
1510                        layer_impl->contents_scale_x(),
1511                        layer_impl->contents_scale_y()))
1512     return false;
1513
1514   // At this point, we think the point does hit the touch event handler region
1515   // on the layer, but we need to walk up the parents to ensure that the layer
1516   // was not clipped in such a way that the hit point actually should not hit
1517   // the layer.
1518   if (PointIsClippedBySurfaceOrClipRect(screen_space_point, layer_impl))
1519     return false;
1520
1521   return true;
1522 }
1523
1524 struct FindWheelEventLayerFunctor {
1525   bool operator()(LayerImpl* layer) const {
1526     return layer->have_wheel_event_handlers();
1527   }
1528 };
1529
1530 LayerImpl* LayerTreeImpl::FindLayerWithWheelHandlerThatIsHitByPoint(
1531     const gfx::PointF& screen_space_point) {
1532   if (!root_layer())
1533     return NULL;
1534   bool update_lcd_text = false;
1535   if (!UpdateDrawProperties(update_lcd_text))
1536     return NULL;
1537   FindWheelEventLayerFunctor func;
1538   FindClosestMatchingLayerDataForRecursion data_for_recursion;
1539   FindClosestMatchingLayer(screen_space_point, root_layer(), func,
1540                            &data_for_recursion);
1541   return data_for_recursion.closest_match;
1542 }
1543
1544 struct FindTouchEventLayerFunctor {
1545   bool operator()(LayerImpl* layer) const {
1546     return LayerHasTouchEventHandlersAt(screen_space_point, layer);
1547   }
1548   const gfx::PointF screen_space_point;
1549 };
1550
1551 LayerImpl* LayerTreeImpl::FindLayerThatIsHitByPointInTouchHandlerRegion(
1552     const gfx::PointF& screen_space_point) {
1553   if (!root_layer())
1554     return NULL;
1555   bool update_lcd_text = false;
1556   if (!UpdateDrawProperties(update_lcd_text))
1557     return NULL;
1558   FindTouchEventLayerFunctor func = {screen_space_point};
1559   FindClosestMatchingLayerDataForRecursion data_for_recursion;
1560   FindClosestMatchingLayer(
1561       screen_space_point, root_layer(), func, &data_for_recursion);
1562   return data_for_recursion.closest_match;
1563 }
1564
1565 void LayerTreeImpl::RegisterSelection(const LayerSelectionBound& start,
1566                                       const LayerSelectionBound& end) {
1567   selection_start_ = start;
1568   selection_end_ = end;
1569 }
1570
1571 static ViewportSelectionBound ComputeViewportSelection(
1572     const LayerSelectionBound& layer_bound,
1573     LayerImpl* layer,
1574     float device_scale_factor) {
1575   ViewportSelectionBound viewport_bound;
1576   viewport_bound.type = layer_bound.type;
1577
1578   if (!layer || layer_bound.type == SELECTION_BOUND_EMPTY)
1579     return viewport_bound;
1580
1581   gfx::PointF layer_scaled_top = gfx::ScalePoint(layer_bound.edge_top,
1582                                                  layer->contents_scale_x(),
1583                                                  layer->contents_scale_y());
1584   gfx::PointF layer_scaled_bottom = gfx::ScalePoint(layer_bound.edge_bottom,
1585                                                     layer->contents_scale_x(),
1586                                                     layer->contents_scale_y());
1587
1588   bool clipped = false;
1589   gfx::PointF screen_top = MathUtil::MapPoint(
1590       layer->screen_space_transform(), layer_scaled_top, &clipped);
1591   gfx::PointF screen_bottom = MathUtil::MapPoint(
1592       layer->screen_space_transform(), layer_scaled_bottom, &clipped);
1593
1594   const float inv_scale = 1.f / device_scale_factor;
1595   viewport_bound.edge_top = gfx::ScalePoint(screen_top, inv_scale);
1596   viewport_bound.edge_bottom = gfx::ScalePoint(screen_bottom, inv_scale);
1597
1598   // The bottom edge point is used for visibility testing as it is the logical
1599   // focal point for bound selection handles (this may change in the future).
1600   // Shifting the visibility point fractionally inward ensures that neighboring
1601   // or logically coincident layers aligned to integral DPI coordinates will not
1602   // spuriously occlude the bound.
1603   gfx::Vector2dF visibility_offset = layer_scaled_top - layer_scaled_bottom;
1604   visibility_offset.Scale(device_scale_factor / visibility_offset.Length());
1605   gfx::PointF visibility_point = layer_scaled_bottom + visibility_offset;
1606   if (visibility_point.x() <= 0)
1607     visibility_point.set_x(visibility_point.x() + device_scale_factor);
1608   visibility_point = MathUtil::MapPoint(
1609       layer->screen_space_transform(), visibility_point, &clipped);
1610
1611   float intersect_distance = 0.f;
1612   viewport_bound.visible =
1613       PointHitsLayer(layer, visibility_point, &intersect_distance);
1614
1615   return viewport_bound;
1616 }
1617
1618 void LayerTreeImpl::GetViewportSelection(ViewportSelectionBound* start,
1619                                          ViewportSelectionBound* end) {
1620   DCHECK(start);
1621   DCHECK(end);
1622
1623   *start = ComputeViewportSelection(
1624       selection_start_,
1625       selection_start_.layer_id ? LayerById(selection_start_.layer_id) : NULL,
1626       device_scale_factor());
1627   if (start->type == SELECTION_BOUND_CENTER ||
1628       start->type == SELECTION_BOUND_EMPTY) {
1629     *end = *start;
1630   } else {
1631     *end = ComputeViewportSelection(
1632         selection_end_,
1633         selection_end_.layer_id ? LayerById(selection_end_.layer_id) : NULL,
1634         device_scale_factor());
1635   }
1636 }
1637
1638 void LayerTreeImpl::InputScrollAnimationFinished() {
1639   layer_tree_host_impl_->ScrollEnd();
1640 }
1641
1642 bool LayerTreeImpl::SmoothnessTakesPriority() const {
1643   return layer_tree_host_impl_->GetTreePriority() == SMOOTHNESS_TAKES_PRIORITY;
1644 }
1645
1646 BlockingTaskRunner* LayerTreeImpl::BlockingMainThreadTaskRunner() const {
1647   return proxy()->blocking_main_thread_task_runner();
1648 }
1649
1650 void LayerTreeImpl::SetPendingPageScaleAnimation(
1651     scoped_ptr<PendingPageScaleAnimation> pending_animation) {
1652   pending_page_scale_animation_ = pending_animation.Pass();
1653 }
1654
1655 scoped_ptr<PendingPageScaleAnimation>
1656     LayerTreeImpl::TakePendingPageScaleAnimation() {
1657   return pending_page_scale_animation_.Pass();
1658 }
1659
1660 }  // namespace cc