cc: Clean up root_layer code in LTI

cc/trees/occlusion_tracker_unittest.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/occlusion_tracker.h"
 
 #include <stddef.h>
 
 #include "cc/base/math_util.h"
 #include "cc/layers/layer.h"
@@ skipping 87 matching lines @@
   TestContentLayerImpl* CreateRoot(const gfx::Transform& transform,
                                    const gfx::PointF& position,
                                    const gfx::Size& bounds) {
     LayerTreeImpl* tree = host_->host_impl()->active_tree();
     int id = next_layer_impl_id_++;
     std::unique_ptr<TestContentLayerImpl> layer(
         new TestContentLayerImpl(tree, id));
     TestContentLayerImpl* layer_ptr = layer.get();
     SetProperties(layer_ptr, transform, position, bounds);
 
-    host_->host_impl()->active_tree()->SetRootLayer(std::move(layer));
+    host_->host_impl()->active_tree()->SetRootLayerForTesting(std::move(layer));
 
     layer_ptr->test_properties()->force_render_surface = true;
     SetRootLayerOnMainThread(layer_ptr);
 
     return layer_ptr;
   }
 
   LayerImpl* CreateLayer(LayerImpl* parent,
                          const gfx::Transform& transform,
                          const gfx::PointF& position,
@@ skipping 72 matching lines @@
                                              const gfx::PointF& position,
                                              const gfx::Size& bounds,
                                              bool opaque) {
     TestContentLayerImpl* layer =
         CreateDrawingLayer(parent, transform, position, bounds, opaque);
     layer->test_properties()->force_render_surface = true;
     return layer;
   }
 
   void DestroyLayers() {
-    host_->host_impl()->active_tree()->SetRootLayer(nullptr);
+    host_->host_impl()->active_tree()->SetRootLayerForTesting(nullptr);
     render_surface_layer_list_impl_.clear();
     replica_layers_.clear();
     mask_layers_.clear();
     ResetLayerIterator();
   }
 
   void CopyOutputCallback(std::unique_ptr<CopyOutputResult> result) {}
 
   void AddCopyRequest(Layer* layer) {
     layer->RequestCopyOfOutput(CopyOutputRequest::CreateBitmapRequest(
         base::Bind(&OcclusionTrackerTest::CopyOutputCallback,
                    base::Unretained(this))));
   }
 
   void AddCopyRequest(LayerImpl* layer) {
     layer->test_properties()->copy_requests.push_back(
         CopyOutputRequest::CreateBitmapRequest(
             base::Bind(&OcclusionTrackerTest::CopyOutputCallback,
                        base::Unretained(this))));
   }
 
   void CalcDrawEtc(TestContentLayerImpl* root) {
-    DCHECK(root == root->layer_tree_impl()->root_layer());
+    root->layer_tree_impl()->BuildLayerListForTesting();
+    DCHECK(root == root->layer_tree_impl()->root_layer_for_testing());
 
     // These occlusion tests attach and detach layers in multiple
     // iterations, so rebuild property trees every time.
     root->layer_tree_impl()->property_trees()->needs_rebuild = true;
 
     FakeLayerTreeHostImpl::RecursiveUpdateNumChildren(root);
 
     LayerTreeHostCommon::CalcDrawPropsImplInputsForTesting inputs(
         root, root->bounds(), &render_surface_layer_list_impl_);
     inputs.can_adjust_raster_scales = true;
@@ skipping 2279 matching lines @@
     EXPECT_EQ(gfx::Rect(),
               occlusion.UnoccludedSurfaceContentRect(
                   surface, gfx::Rect(80, 70, 50, 50)));
   }
 };
 
 ALL_OCCLUSIONTRACKER_TEST(OcclusionTrackerTestUnoccludedSurfaceQuery)
 
 }  // namespace
 }  // namespace cc