cc: Derive draw opacity from property trees

cc/layers/layer.h

 // Copyright 2010 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_LAYERS_LAYER_H_
 #define CC_LAYERS_LAYER_H_
 
 #include <set>
 #include <string>
 #include <vector>
@@ skipping 454 matching lines @@
     needs_push_properties_ = false;
   }
 
   virtual void RunMicroBenchmark(MicroBenchmark* benchmark);
 
   void Set3dSortingContextId(int id);
   int sorting_context_id() const { return sorting_context_id_; }
 
   void set_transform_tree_index(int index) { transform_tree_index_ = index; }
   void set_clip_tree_index(int index) { clip_tree_index_ = index; }
+  void set_opacity_tree_index(int index) { opacity_tree_index_ = index; }
   int clip_tree_index() const { return clip_tree_index_; }
   int transform_tree_index() const { return transform_tree_index_; }
+  int opacity_tree_index() const { return opacity_tree_index_; }
 
   void set_offset_to_transform_parent(gfx::Vector2dF offset) {
     offset_to_transform_parent_ = offset;
   }
   gfx::Vector2dF offset_to_transform_parent() const {
     return offset_to_transform_parent_;
   }
 
   // TODO(vollick): Once we transition to transform and clip trees, rename these
   // functions and related values.  The "from property trees" functions below
   // use the transform and clip trees.  Eventually, we will use these functions
   // to compute the official values, but these functions are retained for
   // testing purposes until we've migrated.
 
   const gfx::Rect& visible_rect_from_property_trees() const {
     return visible_rect_from_property_trees_;
   }
   void set_visible_rect_from_property_trees(const gfx::Rect& rect) {
     visible_rect_from_property_trees_ = rect;
   }
 
   gfx::Transform screen_space_transform_from_property_trees(
       const TransformTree& tree) const;
   gfx::Transform draw_transform_from_property_trees(
       const TransformTree& tree) const;
+  float DrawOpacityFromPropertyTrees(const OpacityTree& tree) const;
 
   // TODO(vollick): These values are temporary and will be removed as soon as
   // render surface determinations are moved out of CDP. They only exist because
   // certain logic depends on whether or not a layer would render to a separate
   // surface, but CDP destroys surfaces and targets it doesn't need, so without
   // this boolean, this is impossible to determine after the fact without
   // wastefully recomputing it. This is public for the time being so that it can
   // be accessed from CDP.
   bool has_render_surface() const {
     return has_render_surface_;
@@ skipping 199 matching lines @@
 
   std::vector<FrameTimingRequest> frame_timing_requests_;
   bool frame_timing_requests_dirty_;
 
   DISALLOW_COPY_AND_ASSIGN(Layer);
 };
 
 }  // namespace cc
 
 #endif  // CC_LAYERS_LAYER_H_