Add a hide_layer_and_subtree() flag to cc::Layer

ui/compositor/layer.h

 // Copyright (c) 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 UI_COMPOSITOR_LAYER_H_
 #define UI_COMPOSITOR_LAYER_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 391 matching lines @@
   Layer* parent_;
 
   // This layer's children, in bottom-to-top stacking order.
   std::vector<Layer*> children_;
 
   gfx::Rect bounds_;
 
   // Visibility of this layer. See SetVisible/IsDrawn for more details.
   bool visible_;
 
-  // Computed based on the visibility of this layer and its ancestors.
-  bool is_drawn_;
-
   bool force_render_surface_;
 
   bool fills_bounds_opaquely_;
 
   // If true the layer is always up to date.
   bool layer_updated_externally_;
 
   // Union of damaged rects, in pixel coordinates, to be used when
   // compositor is ready to paint the content.
   SkRegion damaged_region_;
@@ skipping 55 matching lines @@
   // The size of the delegated frame in DIP, set when SetDelegatedFrame was
   // called.
   gfx::Size delegated_frame_size_in_dip_;
 
   DISALLOW_COPY_AND_ASSIGN(Layer);
 };
 
 }  // namespace ui
 
 #endif  // UI_COMPOSITOR_LAYER_H_