Replace layer id with Element id for tracking scrollbar animation controllers

cc/trees/layer_tree_host_unittest.cc

 // Copyright 2011 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 "cc/trees/layer_tree_host.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <algorithm>
@@ skipping 1732 matching lines @@
     settings->layer_transforms_should_scale_layer_contents = true;
   }
 
   void SetupTree() override {
     root_layer_ = Layer::Create();
     root_layer_->SetBounds(gfx::Size(10, 20));
 
     bool paint_scrollbar = true;
     bool has_thumb = false;
     scrollbar_ = FakePaintedScrollbarLayer::Create(paint_scrollbar, has_thumb,
-                                                   root_layer_->id());
+                                                   root_layer_->id(),
+                                                   root_layer_->element_id());
     scrollbar_->SetPosition(gfx::PointF(0.f, 10.f));
     scrollbar_->SetBounds(gfx::Size(10, 10));
 
     root_layer_->AddChild(scrollbar_);
 
     layer_tree_host()->SetRootLayer(root_layer_);
     LayerTreeHostTest::SetupTree();
     client_.set_bounds(root_layer_->bounds());
   }
 
@@ skipping 1966 matching lines @@
  protected:
   void BeginTest() override { PostSetNeedsCommitToMainThread(); }
 
   void SetupTree() override {
     root_ = Layer::Create();
     root_->SetBounds(gfx::Size(1, 1));
 
     bool paint_scrollbar = true;
     bool has_thumb = false;
     scrollbar_layer_ = FakePaintedScrollbarLayer::Create(
-        paint_scrollbar, has_thumb, root_->id());
+        paint_scrollbar, has_thumb, root_->id(), root_->element_id());
 
     root_->AddChild(scrollbar_layer_);
 
     layer_tree_host()->SetRootLayer(root_);
     LayerTreeHostTest::SetupTree();
   }
 
   void DidCommitAndDrawFrame() override {
     switch (layer_tree_host()->SourceFrameNumber()) {
       case 0:
@@ skipping 3763 matching lines @@
     DCHECK_EQ(hud->scroll_tree_index(), root_layer->scroll_tree_index());
   }
 
   void AfterTest() override {}
 };
 
 SINGLE_AND_MULTI_THREAD_TEST_F(LayerTreeHostTestHudLayerWithLayerLists);
 
 }  // namespace
 }  // namespace cc