cc: Delete the Renderer base class.

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 <memory>
 
@@ skipping 101 matching lines @@
   // only be used on the compositor thread.
   // The caller should call DetachFromClient() on the same thread before
   // destroying the OutputSurface, even if this fails. And BindToClient should
   // not be called twice for a given OutputSurface.
   virtual bool BindToClient(OutputSurfaceClient* client);
 
   // Called by the compositor on the compositor thread. This is a place where
   // thread-specific data for the output surface can be uninitialized.
   virtual void DetachFromClient();
 
+  // Could be something like "start frame" so mac can ensure backbuffer?
   virtual void EnsureBackbuffer();
+  // Called by the Mac subclass, but otherwise unused..
   virtual void DiscardBackbuffer();
 
   virtual void Reshape(const gfx::Size& size,
                        float scale_factor,
                        const gfx::ColorSpace& color_space,
                        bool alpha);
   gfx::Size SurfaceSize() const { return surface_size_; }
   float device_scale_factor() const { return device_scale_factor_; }
 
   // If supported, this causes a ReclaimResources for all resources that are
@@ skipping 73 matching lines @@
   bool external_stencil_test_enabled_ = false;
 
   base::WeakPtrFactory<OutputSurface> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(OutputSurface);
 };
 
 }  // namespace cc
 
 #endif  // CC_OUTPUT_OUTPUT_SURFACE_H_