| Index: cc/trees/layer_tree_host_unittest_animation.cc
 | 
| diff --git a/cc/trees/layer_tree_host_unittest_animation.cc b/cc/trees/layer_tree_host_unittest_animation.cc
 | 
| index 22a3d554b1f093bc4aeb372a24ae23b50d632383..6eb3f4cdf6ee98f58dd69daf520a0638042e1522 100644
 | 
| --- a/cc/trees/layer_tree_host_unittest_animation.cc
 | 
| +++ b/cc/trees/layer_tree_host_unittest_animation.cc
 | 
| @@ -144,7 +144,7 @@ class LayerTreeHostAnimationTestAddAnimation
 | 
|  
 | 
|    void BeginTest() override {
 | 
|      AttachPlayersToTimeline();
 | 
| -    player_->AttachElement(layer_tree_host()->root_layer()->id());
 | 
| +    player_->AttachElement(layer_tree_host()->root_layer()->element_id());
 | 
|      PostAddInstantAnimationToMainThreadPlayer(player_.get());
 | 
|    }
 | 
|  
 | 
| @@ -185,7 +185,7 @@ class LayerTreeHostAnimationTestCheckerboardDoesNotStarveDraws
 | 
|  
 | 
|    void BeginTest() override {
 | 
|      AttachPlayersToTimeline();
 | 
| -    player_->AttachElement(layer_tree_host()->root_layer()->id());
 | 
| +    player_->AttachElement(layer_tree_host()->root_layer()->element_id());
 | 
|      PostAddAnimationToMainThreadPlayer(player_.get());
 | 
|    }
 | 
|  
 | 
| @@ -223,7 +223,7 @@ class LayerTreeHostAnimationTestAnimationsGetDeleted
 | 
|  
 | 
|    void BeginTest() override {
 | 
|      AttachPlayersToTimeline();
 | 
| -    player_->AttachElement(layer_tree_host()->root_layer()->id());
 | 
| +    player_->AttachElement(layer_tree_host()->root_layer()->element_id());
 | 
|      PostAddAnimationToMainThreadPlayer(player_.get());
 | 
|    }
 | 
|  
 | 
| @@ -269,7 +269,7 @@ class LayerTreeHostAnimationTestAddAnimationWithTimingFunction
 | 
|      layer_tree_host()->root_layer()->AddChild(picture_);
 | 
|  
 | 
|      AttachPlayersToTimeline();
 | 
| -    player_child_->AttachElement(picture_->id());
 | 
| +    player_child_->AttachElement(picture_->element_id());
 | 
|    }
 | 
|  
 | 
|    void BeginTest() override {
 | 
| @@ -335,7 +335,7 @@ class LayerTreeHostAnimationTestSynchronizeAnimationStartTimes
 | 
|  
 | 
|      AttachPlayersToTimeline();
 | 
|      player_child_->set_animation_delegate(this);
 | 
| -    player_child_->AttachElement(picture_->id());
 | 
| +    player_child_->AttachElement(picture_->element_id());
 | 
|    }
 | 
|  
 | 
|    void BeginTest() override {
 | 
| @@ -389,7 +389,7 @@ class LayerTreeHostAnimationTestAnimationFinishedEvents
 | 
|   public:
 | 
|    void BeginTest() override {
 | 
|      AttachPlayersToTimeline();
 | 
| -    player_->AttachElement(layer_tree_host()->root_layer()->id());
 | 
| +    player_->AttachElement(layer_tree_host()->root_layer()->element_id());
 | 
|      PostAddInstantAnimationToMainThreadPlayer(player_.get());
 | 
|    }
 | 
|  
 | 
| @@ -425,7 +425,7 @@ class LayerTreeHostAnimationTestDoNotSkipLayersWithAnimatedOpacity
 | 
|      LayerTreeHostAnimationTest::SetupTree();
 | 
|  
 | 
|      AttachPlayersToTimeline();
 | 
| -    player_->AttachElement(update_check_layer_->id());
 | 
| +    player_->AttachElement(update_check_layer_->element_id());
 | 
|    }
 | 
|  
 | 
|    void BeginTest() override {
 | 
| @@ -472,8 +472,8 @@ class LayerTreeHostAnimationTestLayerAddedWithAnimation
 | 
|      if (layer_tree_host()->source_frame_number() == 1) {
 | 
|        AttachPlayersToTimeline();
 | 
|  
 | 
| -      scoped_refptr<Layer> layer = Layer::Create();
 | 
| -      player_->AttachElement(layer->id());
 | 
| +      scoped_refptr<Layer> layer = CreateTestLayer();
 | 
| +      player_->AttachElement(layer->element_id());
 | 
|        player_->set_animation_delegate(this);
 | 
|  
 | 
|        // Any valid AnimationCurve will do here.
 | 
| @@ -624,7 +624,7 @@ class LayerTreeHostAnimationTestCheckerboardDoesntStartAnimations
 | 
|      layer_tree_host()->root_layer()->AddChild(picture_);
 | 
|  
 | 
|      AttachPlayersToTimeline();
 | 
| -    player_child_->AttachElement(picture_->id());
 | 
| +    player_child_->AttachElement(picture_->element_id());
 | 
|      player_child_->set_animation_delegate(this);
 | 
|    }
 | 
|  
 | 
| @@ -713,7 +713,7 @@ class LayerTreeHostAnimationTestScrollOffsetChangesArePropagated
 | 
|      layer_tree_host()->root_layer()->AddChild(scroll_layer_);
 | 
|  
 | 
|      AttachPlayersToTimeline();
 | 
| -    player_child_->AttachElement(scroll_layer_->id());
 | 
| +    player_child_->AttachElement(scroll_layer_->element_id());
 | 
|    }
 | 
|  
 | 
|    void BeginTest() override { PostSetNeedsCommitToMainThread(); }
 | 
| @@ -770,7 +770,7 @@ class LayerTreeHostAnimationTestScrollOffsetAnimationTakeover
 | 
|      layer_tree_host()->root_layer()->AddChild(scroll_layer_);
 | 
|  
 | 
|      AttachPlayersToTimeline();
 | 
| -    player_child_->AttachElement(scroll_layer_->id());
 | 
| +    player_child_->AttachElement(scroll_layer_->element_id());
 | 
|      // Allows NotifyAnimationTakeover to get called.
 | 
|      player_child_->set_animation_delegate(this);
 | 
|    }
 | 
| @@ -789,7 +789,7 @@ class LayerTreeHostAnimationTestScrollOffsetAnimationTakeover
 | 
|    void WillCommitCompleteOnThread(LayerTreeHostImpl* host_impl) override {
 | 
|      if (host_impl->sync_tree()->source_frame_number() == 0) {
 | 
|        host_impl->animation_host()->ImplOnlyScrollAnimationCreate(
 | 
| -          scroll_layer_->id(), gfx::ScrollOffset(650.f, 750.f),
 | 
| +          scroll_layer_->element_id(), gfx::ScrollOffset(650.f, 750.f),
 | 
|            gfx::ScrollOffset(10, 20));
 | 
|      }
 | 
|    }
 | 
| @@ -838,7 +838,7 @@ class LayerTreeHostAnimationTestScrollOffsetAnimationRemoval
 | 
|      animation->set_needs_synchronized_start_time(true);
 | 
|  
 | 
|      AttachPlayersToTimeline();
 | 
| -    player_child_->AttachElement(scroll_layer_->id());
 | 
| +    player_child_->AttachElement(scroll_layer_->element_id());
 | 
|      player_child_->AddAnimation(std::move(animation));
 | 
|    }
 | 
|  
 | 
| @@ -944,16 +944,16 @@ class LayerTreeHostAnimationTestAnimationsAddedToNewAndExistingLayers
 | 
|  
 | 
|    void DidCommit() override {
 | 
|      if (layer_tree_host()->source_frame_number() == 1) {
 | 
| -      player_->AttachElement(layer_tree_host()->root_layer()->id());
 | 
| +      player_->AttachElement(layer_tree_host()->root_layer()->element_id());
 | 
|        AddAnimatedTransformToPlayer(player_.get(), 4, 1, 1);
 | 
|      } else if (layer_tree_host()->source_frame_number() == 2) {
 | 
|        AddOpacityTransitionToPlayer(player_.get(), 1, 0.f, 0.5f, true);
 | 
|  
 | 
| -      scoped_refptr<Layer> layer = Layer::Create();
 | 
| +      scoped_refptr<Layer> layer = CreateTestLayer();
 | 
|        layer_tree_host()->root_layer()->AddChild(layer);
 | 
|        layer->SetBounds(gfx::Size(4, 4));
 | 
|  
 | 
| -      player_child_->AttachElement(layer->id());
 | 
| +      player_child_->AttachElement(layer->element_id());
 | 
|        player_child_->set_animation_delegate(this);
 | 
|        AddOpacityTransitionToPlayer(player_child_.get(), 1, 0.f, 0.5f, true);
 | 
|      }
 | 
| @@ -1041,7 +1041,7 @@ class LayerTreeHostAnimationTestPendingTreeAnimatesFirstCommit
 | 
|      layer_->SetTransform(start_transform);
 | 
|  
 | 
|      layer_tree_host()->root_layer()->AddChild(layer_);
 | 
| -    player_->AttachElement(layer_->id());
 | 
| +    player_->AttachElement(layer_->element_id());
 | 
|  
 | 
|      AttachPlayersToTimeline();
 | 
|    }
 | 
| @@ -1107,13 +1107,13 @@ class LayerTreeHostAnimationTestAnimatedLayerRemovedAndAdded
 | 
|   public:
 | 
|    void SetupTree() override {
 | 
|      LayerTreeHostAnimationTest::SetupTree();
 | 
| -    layer_ = Layer::Create();
 | 
| +    layer_ = CreateTestLayer();
 | 
|      layer_->SetBounds(gfx::Size(4, 4));
 | 
|      layer_tree_host()->root_layer()->AddChild(layer_);
 | 
|  
 | 
|      layer_tree_host()->animation_host()->AddAnimationTimeline(timeline_.get());
 | 
|      timeline_->AttachPlayer(player_.get());
 | 
| -    player_->AttachElement(layer_->id());
 | 
| +    player_->AttachElement(layer_->element_id());
 | 
|      DCHECK(player_->element_animations());
 | 
|  
 | 
|      AddOpacityTransitionToPlayer(player_.get(), 10000.0, 0.1f, 0.9f, true);
 | 
| @@ -1189,14 +1189,14 @@ class LayerTreeHostAnimationTestAddAnimationAfterAnimating
 | 
|   public:
 | 
|    void SetupTree() override {
 | 
|      LayerTreeHostAnimationTest::SetupTree();
 | 
| -    layer_ = Layer::Create();
 | 
| +    layer_ = CreateTestLayer();
 | 
|      layer_->SetBounds(gfx::Size(4, 4));
 | 
|      layer_tree_host()->root_layer()->AddChild(layer_);
 | 
|  
 | 
|      AttachPlayersToTimeline();
 | 
|  
 | 
| -    player_->AttachElement(layer_tree_host()->root_layer()->id());
 | 
| -    player_child_->AttachElement(layer_->id());
 | 
| +    player_->AttachElement(layer_tree_host()->root_layer()->element_id());
 | 
| +    player_child_->AttachElement(layer_->element_id());
 | 
|    }
 | 
|  
 | 
|    void BeginTest() override { PostSetNeedsCommitToMainThread(); }
 | 
| @@ -1257,8 +1257,8 @@ class LayerTreeHostAnimationTestRemoveAnimation
 | 
|  
 | 
|      AttachPlayersToTimeline();
 | 
|  
 | 
| -    player_->AttachElement(layer_tree_host()->root_layer()->id());
 | 
| -    player_child_->AttachElement(layer_->id());
 | 
| +    player_->AttachElement(layer_tree_host()->root_layer()->element_id());
 | 
| +    player_child_->AttachElement(layer_->element_id());
 | 
|    }
 | 
|  
 | 
|    void BeginTest() override { PostSetNeedsCommitToMainThread(); }
 | 
| @@ -1336,7 +1336,7 @@ class LayerTreeHostAnimationTestIsAnimating
 | 
|      layer_tree_host()->root_layer()->AddChild(layer_);
 | 
|  
 | 
|      AttachPlayersToTimeline();
 | 
| -    player_->AttachElement(layer_->id());
 | 
| +    player_->AttachElement(layer_->element_id());
 | 
|    }
 | 
|  
 | 
|    void BeginTest() override { PostSetNeedsCommitToMainThread(); }
 | 
| @@ -1418,8 +1418,8 @@ class LayerTreeHostAnimationTestAnimationFinishesDuringCommit
 | 
|  
 | 
|      AttachPlayersToTimeline();
 | 
|  
 | 
| -    player_->AttachElement(layer_tree_host()->root_layer()->id());
 | 
| -    player_child_->AttachElement(layer_->id());
 | 
| +    player_->AttachElement(layer_tree_host()->root_layer()->element_id());
 | 
| +    player_child_->AttachElement(layer_->element_id());
 | 
|    }
 | 
|  
 | 
|    void BeginTest() override { PostSetNeedsCommitToMainThread(); }
 | 
| @@ -1492,7 +1492,7 @@ class LayerTreeHostAnimationTestNotifyAnimationFinished
 | 
|      layer_tree_host()->root_layer()->AddChild(picture_);
 | 
|  
 | 
|      AttachPlayersToTimeline();
 | 
| -    player_->AttachElement(picture_->id());
 | 
| +    player_->AttachElement(picture_->element_id());
 | 
|      player_->set_animation_delegate(this);
 | 
|    }
 | 
|  
 | 
| @@ -1542,7 +1542,7 @@ class LayerTreeHostAnimationTestSetPotentiallyAnimatingOnLacDestruction
 | 
|  
 | 
|      LayerTreeHostAnimationTest::SetupTree();
 | 
|      AttachPlayersToTimeline();
 | 
| -    player_->AttachElement(layer_tree_host()->root_layer()->id());
 | 
| +    player_->AttachElement(layer_tree_host()->root_layer()->element_id());
 | 
|      AddAnimatedTransformToPlayer(player_.get(), 1.0, 5, 5);
 | 
|    }
 | 
|  
 | 
| @@ -1626,8 +1626,8 @@ class LayerTreeHostAnimationTestRebuildPropertyTreesOnAnimationSetNeedsCommit
 | 
|  
 | 
|      AttachPlayersToTimeline();
 | 
|  
 | 
| -    player_->AttachElement(layer_tree_host()->root_layer()->id());
 | 
| -    player_child_->AttachElement(layer_->id());
 | 
| +    player_->AttachElement(layer_tree_host()->root_layer()->element_id());
 | 
| +    player_child_->AttachElement(layer_->element_id());
 | 
|    }
 | 
|  
 | 
|    void BeginTest() override { PostSetNeedsCommitToMainThread(); }
 | 
| 
 |