cc : Simplify layer skipping logic

cc/trees/draw_property_utils.h

 // 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.
 
 #ifndef CC_TREES_DRAW_PROPERTY_UTILS_H_
 #define CC_TREES_DRAW_PROPERTY_UTILS_H_
 
 #include "cc/base/cc_export.h"
 #include "cc/layers/layer_collections.h"
 
@@ skipping 21 matching lines @@
 // that |transform_tree| has been updated via |ComputeTransforms|.
 void CC_EXPORT ComputeClips(ClipTree* clip_tree,
                             const TransformTree& transform_tree,
                             bool non_root_surfaces_enabled);
 
 // Computes combined (screen space) transforms for every node in the transform
 // tree. This must be done prior to calling |ComputeClips|.
 void CC_EXPORT ComputeTransforms(TransformTree* transform_tree);
 
 // Computes screen space opacity for every node in the opacity tree.
-void CC_EXPORT ComputeEffects(EffectTree* effect_tree);
+bool CC_EXPORT ComputeEffects(EffectTree* effect_tree);
 
 void CC_EXPORT BuildPropertyTreesAndComputeVisibleRects(
     LayerImpl* root_layer,
     const LayerImpl* page_scale_layer,
     const LayerImpl* inner_viewport_scroll_layer,
     const LayerImpl* outer_viewport_scroll_layer,
     const LayerImpl* overscroll_elasticity_layer,
     const gfx::Vector2dF& elastic_overscroll,
     float page_scale_factor,
     float device_scale_factor,
@@ skipping 73 matching lines @@
 
 void CC_EXPORT
 UpdateElasticOverscroll(PropertyTrees* property_trees,
                         const Layer* overscroll_elasticity_layer,
                         const gfx::Vector2dF& elastic_overscroll);
 
 }  // namespace draw_property_utils
 }  // namespace cc
 
 #endif  // CC_TREES_DRAW_PROPERTY_UTILS_H_