cc : Update render surfaces using LayerListIterator instead of treewalk

cc/trees/draw_property_utils.cc

Index: cc/trees/draw_property_utils.cc
diff --git a/cc/trees/draw_property_utils.cc b/cc/trees/draw_property_utils.cc
index d31fb067ea8273269f0c0d71aee57a0c4f8e69b9..e8e1e6fe4a743daa4819690f8c6998c83fc97526 100644
--- a/cc/trees/draw_property_utils.cc
+++ b/cc/trees/draw_property_utils.cc
@@ -452,9 +452,8 @@ void FindLayersThatNeedUpdates(
   }
 }
 
-template <typename LayerType>
 void UpdateRenderSurfacesWithEffectTreeInternal(EffectTree* effect_tree,
-                                                LayerType* layer) {
+                                                Layer* layer) {
   EffectNode* node = effect_tree->Node(layer->effect_tree_index());
 
   if (node->owner_id == layer->id() && node->data.has_render_surface)
@@ -463,13 +462,12 @@ void UpdateRenderSurfacesWithEffectTreeInternal(EffectTree* effect_tree,
     layer->SetHasRenderSurface(false);
 
   for (size_t i = 0; i < layer->children().size(); ++i) {
-    UpdateRenderSurfacesWithEffectTreeInternal<LayerType>(effect_tree,
-                                                          layer->child_at(i));
+    UpdateRenderSurfacesWithEffectTreeInternal(effect_tree, layer->child_at(i));
   }
 }
 
 void UpdateRenderSurfacesWithEffectTree(EffectTree* effect_tree, Layer* layer) {
-  UpdateRenderSurfacesWithEffectTreeInternal<Layer>(effect_tree, layer);
+  UpdateRenderSurfacesWithEffectTreeInternal(effect_tree, layer);

[ajuma, 2016/03/22 14:41:54]

Since there's no templating anymore, can we remove the indirection here and just
rename UpdateRenderSurfacesWithEffectTreeInternal to
UpdateRenderSurfacesWithEffectTree?

[jaydasika, 2016/03/22 20:48:36]

Done.

 }
 
 void UpdateRenderSurfacesNonRootSurfacesDisabled(LayerImpl* layer) {

[ajuma, 2016/03/22 14:41:54]

Can this be deleted now?

[jaydasika, 2016/03/22 20:48:36]

Done.

@@ -483,10 +481,16 @@ void UpdateRenderSurfacesNonRootSurfacesDisabled(LayerImpl* layer) {
 void UpdateRenderSurfacesWithEffectTree(EffectTree* effect_tree,
                                         bool non_root_surfaces_enabled,
                                         LayerImpl* layer) {
-  if (!non_root_surfaces_enabled)
-    UpdateRenderSurfacesNonRootSurfacesDisabled(layer);
+  if (!non_root_surfaces_enabled) {
+    layer->SetHasRenderSurface(!layer->parent());
+    return;
+  }
+  EffectNode* node = effect_tree->Node(layer->effect_tree_index());
+
+  if (node->owner_id == layer->id() && node->data.has_render_surface)
+    layer->SetHasRenderSurface(true);
   else
-    UpdateRenderSurfacesWithEffectTreeInternal<LayerImpl>(effect_tree, layer);
+    layer->SetHasRenderSurface(false);

[ajuma, 2016/03/22 14:41:55]

To avoid code duplication, how about turning this logic into a (templated)
UpdateRenderSurfaceForLayer that's called while recursing over the layer tree
for Layer and while iterating over the tree for LayerImpl?

[jaydasika, 2016/03/22 20:48:34]

Done.

 }
 
 }  // namespace
@@ -740,8 +744,9 @@ void ComputeVisibleRects(LayerImpl* root_layer,
                          PropertyTrees* property_trees,
                          bool can_render_to_separate_surface,
                          LayerImplList* visible_layer_list) {
-  UpdateRenderSurfacesWithEffectTree(
-      &property_trees->effect_tree, can_render_to_separate_surface, root_layer);
+  for (auto* layer : *root_layer->layer_tree_impl())
+    UpdateRenderSurfacesWithEffectTree(&property_trees->effect_tree,
+                                       can_render_to_separate_surface, layer);
   if (can_render_to_separate_surface)
     ValidateRenderSurfaces(root_layer);
   LayerImplList update_layer_list;