cc: Clean up root_layer code in LTI

cc/trees/layer_tree_host_unittest_scroll.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 "base/location.h"
 #include "base/memory/weak_ptr.h"
 #include "base/single_thread_task_runner.h"
 #include "base/threading/thread_task_runner_handle.h"
@@ skipping 92 matching lines @@
       EXPECT_VECTOR_EQ(gfx::ScrollOffsetWithDelta(initial_scroll_,
                                                   scroll_amount_),
                        scroll_layer->scroll_offset());
 
       // Pretend like Javascript updated the scroll position itself.
       scroll_layer->SetScrollOffset(second_scroll_);
     }
   }
 
   void DrawLayersOnThread(LayerTreeHostImpl* impl) override {
-    LayerImpl* root = impl->active_tree()->root_layer();
+    LayerImpl* root = impl->active_tree()->root_layer_for_testing();
     LayerImpl* scroll_layer = impl->OuterViewportScrollLayer();
     EXPECT_VECTOR_EQ(gfx::Vector2d(), ScrollDelta(scroll_layer));
 
     scroll_layer->SetScrollClipLayer(outer_viewport_container_layer_id_);
     scroll_layer->SetBounds(
         gfx::Size(root->bounds().width() + 100, root->bounds().height() + 100));
     scroll_layer->ScrollBy(scroll_amount_);
 
     switch (impl->active_tree()->source_frame_number()) {
       case 0:
@@ skipping 781 matching lines @@
     // We force a second draw here of the first commit before activating
     // the second commit.
     if (impl->active_tree()->source_frame_number() == 0)
       impl->SetNeedsRedraw();
   }
 
   void DrawLayersOnThread(LayerTreeHostImpl* impl) override {
     if (impl->pending_tree())
       impl->SetNeedsRedraw();
 
-    LayerImpl* root = impl->active_tree()->root_layer();
+    LayerImpl* root = impl->active_tree()->root_layer_for_testing();
     LayerImpl* scroll_layer = impl->OuterViewportScrollLayer();
     LayerImpl* pending_root =
         impl->active_tree()->FindPendingTreeLayerById(root->id());
 
     switch (impl->active_tree()->source_frame_number()) {
       case 0:
         if (!impl->pending_tree()) {
           impl->BlockNotifyReadyToActivateForTesting(true);
           EXPECT_VECTOR_EQ(gfx::Vector2d(), ScrollDelta(scroll_layer));
           scroll_layer->ScrollBy(impl_thread_scroll1_);
@@ skipping 98 matching lines @@
         EXPECT_FALSE(
             scroll_layer->layer_tree_host()->LayerNeedsPushPropertiesForTesting(
                 scroll_layer));
         break;
     }
   }
 
   void BeginCommitOnThread(LayerTreeHostImpl* impl) override {
     // Scroll after the 2nd commit has started.
     if (impl->active_tree()->source_frame_number() == 0) {
-      LayerImpl* active_root = impl->active_tree()->root_layer();
+      LayerImpl* active_root = impl->active_tree()->root_layer_for_testing();
       LayerImpl* active_scroll_layer = impl->OuterViewportScrollLayer();
       ASSERT_TRUE(active_root);
       ASSERT_TRUE(active_scroll_layer);
       active_scroll_layer->ScrollBy(impl_thread_scroll_);
       impl->active_tree()->SetPageScaleOnActiveTree(impl_scale_);
     }
   }
 
   void CommitCompleteOnThread(LayerTreeHostImpl* impl) override {
     // We force a second draw here of the first commit before activating
     // the second commit.
-    LayerImpl* active_root = impl->active_tree()->root_layer();
+    LayerImpl* active_root = impl->active_tree()->root_layer_for_testing();
     LayerImpl* active_scroll_layer =
         active_root ? impl->OuterViewportScrollLayer() : NULL;
-    LayerImpl* pending_root = impl->pending_tree()->root_layer();
+    LayerImpl* pending_root = impl->pending_tree()->root_layer_for_testing();
     LayerImpl* pending_scroll_layer =
         impl->pending_tree()->OuterViewportScrollLayer();
 
     ASSERT_TRUE(pending_root);
     ASSERT_TRUE(pending_scroll_layer);
     switch (impl->pending_tree()->source_frame_number()) {
       case 0:
         EXPECT_VECTOR_EQ(
             initial_scroll_,
             ScrollTreeForLayer(pending_scroll_layer)
@@ skipping 560 matching lines @@
     num_scrolls_++;
   }
 
   void AfterTest() override {
     EXPECT_EQ(3, num_commits_);
     EXPECT_EQ(1, num_scrolls_);
   }
 
  private:
   void Scroll(LayerTreeHostImpl* impl) {
-    LayerImpl* root = impl->active_tree()->root_layer();
+    LayerImpl* root = impl->active_tree()->root_layer_for_testing();
     LayerImpl* scroll_layer = impl->OuterViewportScrollLayer();
 
     scroll_layer->SetScrollClipLayer(outer_viewport_container_layer_id_);
     scroll_layer->SetBounds(
         gfx::Size(root->bounds().width() + 100, root->bounds().height() + 100));
     scroll_layer->ScrollBy(scroll_amount_);
   }
 
   gfx::ScrollOffset initial_scroll_;
   gfx::ScrollOffset second_scroll_;
@@ skipping 226 matching lines @@
   int num_impl_commits_;
   int num_aborted_commits_;
   int num_impl_scrolls_;
   int num_draws_;
 };
 
 MULTI_THREAD_TEST_F(LayerTreeHostScrollTestScrollAbortedCommitMFBA);
 
 }  // namespace
 }  // namespace cc