Replace layer id with Element id for tracking scrollbar animation controllers

cc/trees/layer_tree_host_unittest_context.cc

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include "base/memory/ptr_util.h"
 #include "cc/base/filter_operations.h"
 #include "cc/layers/heads_up_display_layer.h"
@@ skipping 953 matching lines @@
     hw_frame_provider_.set_frame(hw_video_frame_);
     scaled_hw_frame_provider_.set_frame(scaled_hw_video_frame_);
 
     // Enable the hud.
     LayerTreeDebugState debug_state;
     debug_state.show_property_changed_rects = true;
     layer_tree_host()->SetDebugState(debug_state);
 
     scoped_refptr<PaintedScrollbarLayer> scrollbar =
         PaintedScrollbarLayer::Create(
-            std::unique_ptr<Scrollbar>(new FakeScrollbar), layer->id());
+            std::unique_ptr<Scrollbar>(new FakeScrollbar), layer->id(),
+            layer->element_id());
     scrollbar->SetBounds(gfx::Size(10, 10));
     scrollbar->SetIsDrawable(true);
     root->AddChild(scrollbar);
 
     layer_tree_host()->SetRootLayer(root);
     LayerTreeHostContextTest::SetupTree();
   }
 
   void BeginTest() override { PostSetNeedsCommitToMainThread(); }
 
@@ skipping 94 matching lines @@
 };
 
 SINGLE_AND_MULTI_THREAD_TEST_F(LayerTreeHostContextTestImplSidePainting);
 
 class ScrollbarLayerLostContext : public LayerTreeHostContextTest {
  public:
   ScrollbarLayerLostContext() : commits_(0) {}
 
   void BeginTest() override {
     scoped_refptr<Layer> scroll_layer = Layer::Create();
-    scrollbar_layer_ =
-        FakePaintedScrollbarLayer::Create(false, true, scroll_layer->id());
+    scrollbar_layer_ = FakePaintedScrollbarLayer::Create(
+        false, true, scroll_layer->id(), scroll_layer->element_id());
     scrollbar_layer_->SetBounds(gfx::Size(10, 100));
     layer_tree_host()->root_layer()->AddChild(scrollbar_layer_);
     layer_tree_host()->root_layer()->AddChild(scroll_layer);
     PostSetNeedsCommitToMainThread();
   }
 
   void AfterTest() override {}
 
   void CommitCompleteOnThread(LayerTreeHostImpl* impl) override {
     LayerTreeHostContextTest::CommitCompleteOnThread(impl);
@@ skipping 535 matching lines @@
 
   FakeContentLayerClient client_;
   int num_draws_ = 0;
 };
 
 MULTI_THREAD_TEST_F(
     LayerTreeHostContextTestLoseWorkerContextDuringPrepareTiles);
 
 }  // namespace
 }  // namespace cc