cc : Don't draw animating layers which are transparent but raster them.

cc/trees/layer_tree_host_common.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_host_common.h"
 
 #include <stddef.h>
 
 #include <algorithm>
 
@@ skipping 360 matching lines @@
     layer->set_contributes_to_drawn_render_surface(false);
 
     bool is_root = layer_tree_impl->IsRootLayer(layer);
 
     bool skip_draw_properties_computation =
         draw_property_utils::LayerShouldBeSkippedForDrawPropertiesComputation(
             layer, property_trees->transform_tree, property_trees->effect_tree);
 
     bool skip_for_invertibility = SkipForInvertibility(layer, property_trees);
 
+    const EffectNode* effect_node =
+        property_trees->effect_tree.Node(layer->effect_tree_index());
+    bool has_animating_opacity_and_hidden =
+        effect_node->has_potential_opacity_animation &&
+        property_trees->effect_tree.EffectiveOpacity(effect_node) == 0.f &&
+        !effect_node->has_copy_request;
+
     bool skip_layer = !is_root && (skip_draw_properties_computation ||
-                                   skip_for_invertibility);
+                                   skip_for_invertibility ||
+                                   has_animating_opacity_and_hidden);
 
-    layer->set_raster_even_if_not_in_rsll(skip_for_invertibility &&
-                                          !skip_draw_properties_computation);
+    bool raster_even_if_not_in_rsll =
+        skip_draw_properties_computation
+            ? false
+            : has_animating_opacity_and_hidden || skip_for_invertibility;
+    layer->set_raster_even_if_not_in_rsll(raster_even_if_not_in_rsll);
     if (skip_layer)
       continue;
 
     bool layer_is_drawn =
         property_trees->effect_tree.Node(layer->effect_tree_index())->is_drawn;
     bool layer_should_be_drawn = draw_property_utils::LayerNeedsUpdate(
         layer, layer_is_drawn, property_trees);
     if (!layer_should_be_drawn)
       continue;
 
@@ skipping 287 matching lines @@
 
 PropertyTrees* GetPropertyTrees(Layer* layer) {
   return layer->layer_tree_host()->property_trees();
 }
 
 PropertyTrees* GetPropertyTrees(LayerImpl* layer) {
   return layer->layer_tree_impl()->property_trees();
 }
 
 }  // namespace cc