cc : Simplify layer skipping logic

cc/trees/layer_tree_impl.h

 // 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.
 
 #ifndef CC_TREES_LAYER_TREE_IMPL_H_
 #define CC_TREES_LAYER_TREE_IMPL_H_
 
 #include <map>
 #include <set>
 #include <string>
@@ skipping 124 matching lines @@
   void SetRootLayer(std::unique_ptr<LayerImpl>);
   bool IsRootLayer(const LayerImpl* layer) const;
   std::unique_ptr<OwnedLayerImplList> DetachLayers();
   void ClearLayers();
 
   void SetPropertyTrees(const PropertyTrees property_trees) {
     property_trees_ = property_trees;
     property_trees_.is_main_thread = false;
     property_trees_.is_active = IsActiveTree();
     property_trees_.transform_tree.set_source_to_parent_updates_allowed(false);
+    // The value of some effect node properties (like is_drawn) depends on
+    // whether we are on the active tree or not. So, we need to update the
+    // effect tree.
+    if (IsActiveTree())
+      property_trees_.effect_tree.set_needs_update(true);
   }
   PropertyTrees* property_trees() { return &property_trees_; }
 
   void UpdatePropertyTreesForBoundsDelta();
 
   void PushPropertiesTo(LayerTreeImpl* tree_impl);
 
   LayerListIterator begin();
   LayerListIterator end();
   LayerListReverseIterator rbegin();
@@ skipping 435 matching lines @@
 
   std::unique_ptr<PendingPageScaleAnimation> pending_page_scale_animation_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(LayerTreeImpl);
 };
 
 }  // namespace cc
 
 #endif  // CC_TREES_LAYER_TREE_IMPL_H_