Fix race conditions in window snapshot code.

cc/trees/layer_tree_host.h

 // 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.
 
 #ifndef CC_TREES_LAYER_TREE_HOST_H_
 #define CC_TREES_LAYER_TREE_HOST_H_
 
 #include <limits>
 #include <list>
 #include <vector>
@@ skipping 194 matching lines @@
   void SetNeedsAnimate();
   virtual void SetNeedsUpdateLayers();
   virtual void SetNeedsCommit();
   virtual void SetNeedsFullTreeSync();
   void SetNeedsRedraw();
   void SetNeedsRedrawRect(gfx::Rect damage_rect);
   bool CommitRequested() const;
 
   void SetNextCommitWaitsForActivation();
 
+  void SetNextCommitForcesRedraw();
+
   void SetAnimationEvents(scoped_ptr<AnimationEventsVector> events,
                           base::Time wall_clock_time);
 
   void SetRootLayer(scoped_refptr<Layer> root_layer);
   Layer* root_layer() { return root_layer_.get(); }
   const Layer* root_layer() const { return root_layer_.get(); }
   void RegisterViewportLayers(
       scoped_refptr<Layer> page_scale_layer,
       scoped_refptr<Layer> inner_viewport_scroll_layer,
       scoped_refptr<Layer> outer_viewport_scroll_layer);
@@ skipping 215 matching lines @@
         : total_num_cc_layers(0),
           total_num_cc_layers_can_use_lcd_text(0),
           total_num_cc_layers_will_use_lcd_text(0) {}
 
     int64 total_num_cc_layers;
     int64 total_num_cc_layers_can_use_lcd_text;
     int64 total_num_cc_layers_will_use_lcd_text;
   };
   LCDTextMetrics lcd_text_metrics_;
   int tree_id_;
+  bool next_commit_forces_redraw_;
 
   scoped_refptr<Layer> page_scale_layer_;
   scoped_refptr<Layer> inner_viewport_scroll_layer_;
   scoped_refptr<Layer> outer_viewport_scroll_layer_;
 
   DISALLOW_COPY_AND_ASSIGN(LayerTreeHost);
 };
 
 }  // namespace cc
 
 #endif  // CC_TREES_LAYER_TREE_HOST_H_