Revert of cc: Make PaintedScrollbarLayer not use ContentsScalingLayer

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 <algorithm>
 
 #include "base/auto_reset.h"
 #include "base/synchronization/lock.h"
@@ skipping 562 matching lines @@
         layer_tree_host()->SetDeviceScaleFactor(4.f);
         break;
       default:
         // No extra commits.
         EXPECT_EQ(2, layer_tree_host()->source_frame_number());
     }
   }
 
   void AfterTest() override {
     EXPECT_EQ(gfx::Size(40, 40).ToString(),
-              scrollbar_->internal_content_bounds().ToString());
+              scrollbar_->content_bounds().ToString());
   }
 
  private:
   FakeContentLayerClient client_;
   scoped_refptr<Layer> root_layer_;
   scoped_refptr<FakePaintedScrollbarLayer> scrollbar_;
 };
 
 SINGLE_AND_MULTI_THREAD_TEST_F(
     LayerTreeHostTestNoExtraCommitFromScrollbarInvalidate);
@@ skipping 5665 matching lines @@
 
   void AfterTest() override { EXPECT_TRUE(did_commit_); }
 
  private:
   bool did_commit_;
 };
 
 SINGLE_AND_MULTI_THREAD_TEST_F(LayerTreeHostTestNoTasksBetweenWillAndDidCommit);
 
 }  // namespace cc