Use MSAA in GPU rasterization if Skia suggests it

cc/output/output_surface.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_OUTPUT_OUTPUT_SURFACE_H_
 #define CC_OUTPUT_OUTPUT_SURFACE_H_
 
 #include <deque>
 
 #include "base/basictypes.h"
@@ skipping 98 matching lines @@
   void SetThrottleFrameProduction(bool enable);
 
   void InitializeBeginFrameEmulation(base::SingleThreadTaskRunner* task_runner,
                                      base::TimeDelta interval);
 
   virtual void EnsureBackbuffer();
   virtual void DiscardBackbuffer();
 
   virtual void Reshape(const gfx::Size& size, float scale_factor);
   virtual gfx::Size SurfaceSize() const;
+  float SurfaceScaleFactor() const;
 
   virtual void BindFramebuffer();
 
   // The implementation may destroy or steal the contents of the CompositorFrame
   // passed in (though it will not take ownership of the CompositorFrame
   // itself).
   virtual void SwapBuffers(CompositorFrame* frame);
 
   // Notifies frame-rate smoothness preference. If true, all non-critical
   // processing should be stopped, or lowered in priority.
@@ skipping 88 matching lines @@
   std::deque<unsigned> available_gpu_latency_query_ids_;
   std::deque<unsigned> pending_gpu_latency_query_ids_;
   RollingTimeDeltaHistory gpu_latency_history_;
 
   DISALLOW_COPY_AND_ASSIGN(OutputSurface);
 };
 
 }  // namespace cc
 
 #endif  // CC_OUTPUT_OUTPUT_SURFACE_H_