cc : Add layer_list to LayerTreeImpl and build it for tests

cc/trees/layer_tree_impl.cc

 // Copyright 2011 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_impl.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <algorithm>
@@ skipping 246 matching lines @@
 
 void LayerTreeImpl::SetRootLayer(std::unique_ptr<LayerImpl> layer) {
   if (root_layer_ && layer.get() != root_layer_)
     RemoveLayer(root_layer_->id());
   root_layer_ = layer.get();
   if (layer)
     AddLayer(std::move(layer));
   layer_tree_host_impl_->OnCanDrawStateChangedForTree();
 }
 
+void LayerTreeImpl::BuildLayerListForTesting() {
+  layer_list_.clear();
+  LayerListIterator<LayerImpl> it(root_layer_);
+  for (; it != LayerListIterator<LayerImpl>(nullptr); ++it) {
+    layer_list_.push_back(*it);
+  }
+}
+
 bool LayerTreeImpl::IsRootLayer(const LayerImpl* layer) const {
   return root_layer_ == layer;
 }
 
 LayerImpl* LayerTreeImpl::InnerViewportScrollLayer() const {
   return LayerById(inner_viewport_scroll_layer_id_);
 }
 
 LayerImpl* LayerTreeImpl::OuterViewportScrollLayer() const {
   return LayerById(outer_viewport_scroll_layer_id_);
@@ skipping 692 matching lines @@
 
     TRACE_EVENT_END1("cc", "LayerTreeImpl::UpdateDrawProperties::UpdateTiles",
                      "layers_updated_count", layers_updated_count);
   }
 
   DCHECK(!needs_update_draw_properties_)
       << "CalcDrawProperties should not set_needs_update_draw_properties()";
   return true;
 }
 
-void LayerTreeImpl::BuildPropertyTreesForTesting() {
+void LayerTreeImpl::BuildLayerListAndPropertyTreesForTesting() {
+  BuildLayerListForTesting();
   PropertyTreeBuilder::PreCalculateMetaInformationForTesting(root_layer_);
   property_trees_.transform_tree.set_source_to_parent_updates_allowed(true);
   PropertyTreeBuilder::BuildPropertyTrees(
       root_layer_, PageScaleLayer(), InnerViewportScrollLayer(),
       OuterViewportScrollLayer(), OverscrollElasticityLayer(),
       elastic_overscroll()->Current(IsActiveTree()),
       current_page_scale_factor(), device_scale_factor(),
       gfx::Rect(DrawViewportSize()), layer_tree_host_impl_->DrawTransform(),
       &property_trees_);
   property_trees_.transform_tree.set_source_to_parent_updates_allowed(false);
@@ skipping 1069 matching lines @@
 }
 
 void LayerTreeImpl::ResetAllChangeTracking() {
   layers_that_should_push_properties_.clear();
   for (auto* layer : *this)
     layer->ResetChangeTracking();
   property_trees_.ResetAllChangeTracking();
 }
 
 }  // namespace cc