cc: Make LayerTreeHost a protected Layer member.

cc/layers/painted_scrollbar_layer_unittest.cc

 // Copyright 2015 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/layers/painted_scrollbar_layer.h"
 
 #include "cc/test/fake_layer_tree_host.h"
 #include "cc/test/fake_layer_tree_host_client.h"
 #include "cc/test/fake_scrollbar.h"
 #include "cc/test/test_task_graph_runner.h"
@@ skipping 24 matching lines @@
       FakeLayerTreeHost::Create(&fake_client_, &task_graph_runner_);
 
   MockScrollbar* scrollbar = new MockScrollbar();
   scoped_refptr<PaintedScrollbarLayer> scrollbar_layer =
       PaintedScrollbarLayer::Create(std::unique_ptr<Scrollbar>(scrollbar), 1);
 
   scrollbar_layer->SetIsDrawable(true);
   scrollbar_layer->SetBounds(gfx::Size(100, 100));
 
   layer_tree_host_->SetRootLayer(scrollbar_layer);
-  EXPECT_EQ(scrollbar_layer->layer_tree_host(), layer_tree_host_.get());
+  EXPECT_EQ(scrollbar_layer->GetLayerTreeHostForTesting(),
+            layer_tree_host_.get());
   scrollbar_layer->SavePaintProperties();
 
   // Request no paint, but expect them to be painted because they have not
   // yet been initialized.
   scrollbar->set_needs_paint_thumb(false);
   scrollbar->set_needs_paint_track(false);
   EXPECT_CALL(*scrollbar, PaintPart(_, THUMB, _)).Times(1);
   EXPECT_CALL(*scrollbar, PaintPart(_, TRACK, _)).Times(1);
   scrollbar_layer->Update();
   Mock::VerifyAndClearExpectations(scrollbar);
@@ skipping 16 matching lines @@
   EXPECT_CALL(*scrollbar, PaintPart(_, THUMB, _)).Times(0);
   EXPECT_CALL(*scrollbar, PaintPart(_, TRACK, _)).Times(1);
   scrollbar->set_needs_paint_thumb(false);
   scrollbar->set_needs_paint_track(true);
   scrollbar_layer->Update();
   Mock::VerifyAndClearExpectations(scrollbar);
 }
 
 }  // namespace
 }  // namespace cc