cc : Update render surfaces using LayerListIterator instead of treewalk

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/animation/layer_animation_controller.h"
 #include "cc/base/math_util.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_++;
     scoped_ptr<TestContentLayerImpl> layer(new TestContentLayerImpl(tree, id));
     TestContentLayerImpl* layer_ptr = layer.get();
     SetProperties(layer_ptr, transform, position, bounds);
 
-    DCHECK(!root_.get());
-    root_ = std::move(layer);
+    host_->host_impl()->active_tree()->SetRootLayer(std::move(layer));
 
     layer_ptr->SetForceRenderSurface(true);
     SetRootLayerOnMainThread(layer_ptr);
 
     return layer_ptr;
   }
 
   LayerImpl* CreateLayer(LayerImpl* parent,
                          const gfx::Transform& transform,
                          const gfx::PointF& position,
@@ skipping 69 matching lines @@
                                              const gfx::PointF& position,
                                              const gfx::Size& bounds,
                                              bool opaque) {
     TestContentLayerImpl* layer =
         CreateDrawingLayer(parent, transform, position, bounds, opaque);
     layer->SetForceRenderSurface(true);
     return layer;
   }
 
   void DestroyLayers() {
-    root_ = nullptr;
+    host_->host_impl()->active_tree()->SetRootLayer(nullptr);
     render_surface_layer_list_impl_.clear();
     replica_layers_.clear();
     mask_layers_.clear();
     ResetLayerIterator();
   }
 
   void CopyOutputCallback(scoped_ptr<CopyOutputResult> result) {}
 
   void AddCopyRequest(Layer* layer) {
     layer->RequestCopyOfOutput(CopyOutputRequest::CreateBitmapRequest(
         base::Bind(&OcclusionTrackerTest::CopyOutputCallback,
                    base::Unretained(this))));
   }
 
   void AddCopyRequest(LayerImpl* layer) {
     std::vector<scoped_ptr<CopyOutputRequest>> requests;
     requests.push_back(CopyOutputRequest::CreateBitmapRequest(base::Bind(
         &OcclusionTrackerTest::CopyOutputCallback, base::Unretained(this))));
     layer->PassCopyRequests(&requests);
   }
 
   void CalcDrawEtc(TestContentLayerImpl* root) {
-    DCHECK(root == root_.get());
+    DCHECK(root == root->layer_tree_impl()->root_layer());
 
     // 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);
 
     root->layer_tree_impl()->IncrementRenderSurfaceListIdForTesting();
     LayerTreeHostCommon::CalcDrawPropsImplInputsForTesting inputs(
         root, root->bounds(), &render_surface_layer_list_impl_,
@@ skipping 71 matching lines @@
 
   void SetMask(LayerImpl* owning_layer, scoped_ptr<LayerImpl> layer) {
     owning_layer->SetMaskLayer(std::move(layer));
   }
 
   bool opaque_layers_;
   FakeLayerTreeHostClient client_;
   TestTaskGraphRunner task_graph_runner_;
   scoped_ptr<FakeLayerTreeHost> host_;
   // These hold ownership of the layers for the duration of the test.
-  scoped_ptr<LayerImpl> root_;
   LayerImplList render_surface_layer_list_impl_;
   LayerIterator layer_iterator_begin_;
   LayerIterator layer_iterator_;
   LayerList replica_layers_;
   LayerList mask_layers_;
   int next_layer_impl_id_;
 };
 
 #define RUN_TEST_IMPL_THREAD_OPAQUE_LAYERS(ClassName)          \
   class ClassName##ImplThreadOpaqueLayers : public ClassName { \
@@ skipping 2188 matching lines @@
     EXPECT_EQ(gfx::Rect(),
               occlusion.UnoccludedSurfaceContentRect(
                   surface, gfx::Rect(80, 70, 50, 50)));
   }
 };
 
 ALL_OCCLUSIONTRACKER_TEST(OcclusionTrackerTestUnoccludedSurfaceQuery)
 
 }  // namespace
 }  // namespace cc