cc: Merge LayerTree into the LayerTreeHost.

cc/trees/layer_tree_host_perftest.cc

Index: cc/trees/layer_tree_host_perftest.cc
diff --git a/cc/trees/layer_tree_host_perftest.cc b/cc/trees/layer_tree_host_perftest.cc
index 77f550fc91ba47980b846a554d345778e9262ca9..1a25a13cb116eb96f4ea7d4806b5fafe9f0e3cfd 100644
--- a/cc/trees/layer_tree_host_perftest.cc
+++ b/cc/trees/layer_tree_host_perftest.cc
@@ -138,11 +138,11 @@ class LayerTreeHostPerfTestJsonReader : public LayerTreeHostPerfTest {
 
   void BuildTree() override {
     gfx::Size viewport = gfx::Size(720, 1038);
-    layer_tree()->SetViewportSize(viewport);
+    layer_tree_host()->SetViewportSize(viewport);
     scoped_refptr<Layer> root = ParseTreeFromJson(json_,
                                                   &fake_content_layer_client_);
     ASSERT_TRUE(root.get());
-    layer_tree()->SetRootLayer(root);
+    layer_tree_host()->SetRootLayer(root);
     fake_content_layer_client_.set_bounds(viewport);
   }
 
@@ -187,7 +187,7 @@ class LayerTreeHostPerfTestLeafInvalidates
     LayerTreeHostPerfTestJsonReader::BuildTree();
 
     // Find a leaf layer.
-    for (layer_to_invalidate_ = layer_tree()->root_layer();
+    for (layer_to_invalidate_ = layer_tree_host()->root_layer();
          layer_to_invalidate_->children().size();
          layer_to_invalidate_ = layer_to_invalidate_->children()[0].get()) {
     }
@@ -228,7 +228,7 @@ class ScrollingLayerTreePerfTest : public LayerTreeHostPerfTestJsonReader {
 
   void BuildTree() override {
     LayerTreeHostPerfTestJsonReader::BuildTree();
-    scrollable_ = layer_tree()->root_layer()->children()[1];
+    scrollable_ = layer_tree_host()->root_layer()->children()[1];
     ASSERT_TRUE(scrollable_.get());
   }
 
@@ -264,7 +264,7 @@ class BrowserCompositorInvalidateLayerTreePerfTest
 
   void BuildTree() override {
     LayerTreeHostPerfTestJsonReader::BuildTree();
-    tab_contents_ = static_cast<TextureLayer*>(layer_tree()
+    tab_contents_ = static_cast<TextureLayer*>(layer_tree_host()
                                                    ->root_layer()
                                                    ->children()[0]
                                                    ->children()[0]