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