cc: Clean up root_layer code in LTI

cc/trees/layer_tree_host_unittest_context.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 <stddef.h>
 #include <stdint.h>
 
 #include "base/memory/ptr_util.h"
 #include "cc/layers/heads_up_display_layer.h"
 #include "cc/layers/layer_impl.h"
@@ skipping 737 matching lines @@
     if (num_commits_ > 1)
       return;
     ++num_commits_;
     if (!lose_after_evict_) {
       LoseContext();
       lost_context_ = true;
     }
   }
 
   void DrawLayersOnThread(LayerTreeHostImpl* impl) override {
-    FakePictureLayerImpl* picture_impl =
-        static_cast<FakePictureLayerImpl*>(impl->active_tree()->root_layer());
+    FakePictureLayerImpl* picture_impl = static_cast<FakePictureLayerImpl*>(
+        impl->active_tree()->root_layer_for_testing());
     EXPECT_TRUE(picture_impl->HighResTiling()
                     ->TileAt(0, 0)
                     ->draw_info()
                     .IsReadyToDraw());
 
     impl_host_ = impl;
     if (lost_context_)
       EndTest();
   }
 
@@ skipping 78 matching lines @@
   void BeginTest() override { PostSetNeedsCommitToMainThread(); }
 
   void DidActivateTreeOnThread(LayerTreeHostImpl* host_impl) override {
     LayerTreeHostContextTest::DidActivateTreeOnThread(host_impl);
 
     FakePictureLayerImpl* root_picture = NULL;
     FakePictureLayerImpl* child_picture = NULL;
     FakePictureLayerImpl* grandchild_picture = NULL;
 
     root_picture = static_cast<FakePictureLayerImpl*>(
-        host_impl->active_tree()->root_layer());
+        host_impl->active_tree()->root_layer_for_testing());
     child_picture = static_cast<FakePictureLayerImpl*>(
         host_impl->active_tree()->LayerById(child_->id()));
     grandchild_picture = static_cast<FakePictureLayerImpl*>(
         host_impl->active_tree()->LayerById(grandchild_->id()));
 
     ++num_commits_;
     switch (num_commits_) {
       case 1:
         EXPECT_EQ(0u, root_picture->release_resources_count());
         EXPECT_EQ(0u, child_picture->release_resources_count());
@@ skipping 734 matching lines @@
   void AfterTest() override {}
 
   bool deferred_;
 };
 
 SINGLE_AND_MULTI_THREAD_TEST_F(
     LayerTreeHostContextTestLoseAfterSendingBeginMainFrame);
 
 }  // namespace
 }  // namespace cc