cc: Clean up root_layer code in LTI

cc/trees/layer_tree_host_unittest_occlusion.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 "cc/trees/layer_tree_host.h"
 
 #include "cc/layers/layer.h"
 #include "cc/layers/picture_layer.h"
 #include "cc/test/fake_content_layer_client.h"
 #include "cc/test/layer_tree_test.h"
@@ skipping 30 matching lines @@
     child_->SetIsDrawable(true);
     root->AddChild(child_);
 
     layer_tree_host()->SetRootLayer(root);
     LayerTreeTest::SetupTree();
   }
 
   void BeginTest() override { PostSetNeedsCommitToMainThread(); }
 
   void DrawLayersOnThread(LayerTreeHostImpl* impl) override {
-    LayerImpl* root = impl->active_tree()->root_layer();
+    LayerImpl* root = impl->active_tree()->root_layer_for_testing();
     LayerImpl* child = impl->active_tree()->LayerById(child_->id());
 
     // Verify the draw properties are valid.
     EXPECT_TRUE(root->is_drawn_render_surface_layer_list_member());
     EXPECT_TRUE(child->is_drawn_render_surface_layer_list_member());
 
     EXPECT_OCCLUSION_EQ(
         Occlusion(child->DrawTransform(), SimpleEnclosedRegion(),
                   SimpleEnclosedRegion()),
         child->draw_properties().occlusion_in_content_space);
@@ skipping 35 matching lines @@
     child2->SetIsDrawable(true);
     root->AddChild(child2);
 
     layer_tree_host()->SetRootLayer(root);
     LayerTreeTest::SetupTree();
   }
 
   void BeginTest() override { PostSetNeedsCommitToMainThread(); }
 
   void DrawLayersOnThread(LayerTreeHostImpl* impl) override {
-    LayerImpl* root = impl->active_tree()->root_layer();
+    LayerImpl* root = impl->active_tree()->root_layer_for_testing();
     LayerImpl* child = impl->active_tree()->LayerById(child_->id());
     RenderSurfaceImpl* surface = child->render_surface();
 
     // Verify the draw properties are valid.
     EXPECT_TRUE(root->is_drawn_render_surface_layer_list_member());
     EXPECT_TRUE(child->is_drawn_render_surface_layer_list_member());
     EXPECT_TRUE(child->has_render_surface());
     EXPECT_EQ(child->render_surface(), child->render_target());
 
     EXPECT_OCCLUSION_EQ(
@@ skipping 46 matching lines @@
     root->AddChild(child2);
 
     layer_tree_host()->SetRootLayer(root);
     LayerTreeTest::SetupTree();
     client_.set_bounds(root->bounds());
   }
 
   void BeginTest() override { PostSetNeedsCommitToMainThread(); }
 
   void DrawLayersOnThread(LayerTreeHostImpl* impl) override {
-    LayerImpl* root = impl->active_tree()->root_layer();
+    LayerImpl* root = impl->active_tree()->root_layer_for_testing();
     LayerImpl* child = impl->active_tree()->LayerById(child_->id());
     RenderSurfaceImpl* surface = child->render_surface();
     LayerImpl* mask = surface->MaskLayer();
 
     // Verify the draw properties are valid.
     EXPECT_TRUE(root->is_drawn_render_surface_layer_list_member());
     EXPECT_TRUE(child->is_drawn_render_surface_layer_list_member());
     EXPECT_TRUE(child->has_render_surface());
     EXPECT_EQ(child->render_surface(), child->render_target());
 
@@ skipping 120 matching lines @@
     root->AddChild(child2);
 
     layer_tree_host()->SetRootLayer(root);
     LayerTreeTest::SetupTree();
     client_.set_bounds(root->bounds());
   }
 
   void BeginTest() override { PostSetNeedsCommitToMainThread(); }
 
   void DrawLayersOnThread(LayerTreeHostImpl* impl) override {
-    LayerImpl* root = impl->active_tree()->root_layer();
+    LayerImpl* root = impl->active_tree()->root_layer_for_testing();
     LayerImpl* child = impl->active_tree()->LayerById(child_->id());
     RenderSurfaceImpl* surface = child->render_surface();
     LayerImpl* mask = surface->MaskLayer();
 
     // Verify the draw properties are valid.
     EXPECT_TRUE(root->is_drawn_render_surface_layer_list_member());
     EXPECT_TRUE(child->is_drawn_render_surface_layer_list_member());
     EXPECT_TRUE(child->has_render_surface());
     EXPECT_EQ(child->render_surface(), child->render_target());
 
@@ skipping 16 matching lines @@
  private:
   FakeContentLayerClient client_;
   scoped_refptr<Layer> child_;
 };
 
 SINGLE_AND_MULTI_THREAD_TEST_F(
     LayerTreeHostOcclusionTestDrawPropertiesInsideReplica);
 
 }  // namespace
 }  // namespace cc