cc: Main thread skip single layers instead of subtrees

cc/trees/property_tree_builder.cc

 // Copyright 2014 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/property_tree_builder.h"
 
 #include <stddef.h>
 
 #include <map>
 #include <set>
@@ skipping 614 matching lines @@
       node.data.transform_id =
           data_from_ancestor.transform_tree->next_available_id();
     }
     node.data.clip_id = data_from_ancestor.clip_tree_parent;
     EffectNode* parent_node = data_for_children->effect_tree->Node(parent_id);
     node.data.node_or_ancestor_has_background_filters =
         parent_node->data.node_or_ancestor_has_background_filters ||
         node.data.has_background_filters;
     node.data.to_screen_opacity_is_animated =
         parent_node->data.to_screen_opacity_is_animated || has_animated_opacity;
+    node.data.to_screen_opacity_can_animate_on_impl =
+        parent_node->data.to_screen_opacity_can_animate_on_impl &&
+        layer->OpacityCanAnimateOnImplThread();

[ajuma, 2016/04/06 19:49:29]

I believe to_screen_opacity_is_animated already accounts for this, so this
shouldn't be needed (see the definition of IsAnimatingOpacity, which is used to
compute has_animated_opacity).

[sunxd, 2016/04/07 15:37:13]

Done.

   } else {
     // Root render surface acts the unbounded and untransformed to draw content
     // into. Transform node created from root layer (includes device scale
     // factor) and clip node created from root layer (include viewports) applies
     // to root render surface's content, but not root render surface itself.
     node.data.transform_id = kRootPropertyTreeNodeId;
     node.data.clip_id = kRootPropertyTreeNodeId;
     node.data.node_or_ancestor_has_background_filters =
         node.data.has_background_filters;
     node.data.to_screen_opacity_is_animated = has_animated_opacity;
+    node.data.to_screen_opacity_can_animate_on_impl =
+        layer->OpacityCanAnimateOnImplThread();
   }
   node.data.target_id =
       should_create_render_surface
           ? data_from_ancestor.effect_tree->next_available_id()
           : data_for_children->render_target;
   data_for_children->effect_tree_parent =
       data_for_children->effect_tree->Insert(node, parent_id);
   layer->SetEffectTreeIndex(data_for_children->effect_tree_parent);
   if (should_create_render_surface) {
     data_for_children->compound_transform_since_render_target =
@@ skipping 354 matching lines @@
   if (SkColorGetA(color) != 255)
     color = SkColorSetA(color, 255);
   BuildPropertyTreesTopLevelInternal(
       root_layer, page_scale_layer, inner_viewport_scroll_layer,
       outer_viewport_scroll_layer, overscroll_elasticity_layer,
       elastic_overscroll, page_scale_factor, device_scale_factor, viewport,
       device_transform, property_trees, color);
 }
 
 }  // namespace cc