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