Drop frontbuffers with ui-use-gpu-process, synchronized with browser, decoupled from backbuffer dro…

ui/gfx/gl/gl_surface.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_GFX_GL_GL_SURFACE_H_
 #define UI_GFX_GL_GL_SURFACE_H_
 #pragma once
 
 #include "base/memory/ref_counted.h"
 #include "build/build_config.h"
@@ skipping 53 matching lines @@
 
   // Copy part of the backbuffer to the frontbuffer.
   virtual bool PostSubBuffer(int x, int y, int width, int height);
 
   static bool InitializeOneOff();
 
   // Called after a context is made current with this surface. Returns false
   // on error.
   virtual bool OnMakeCurrent(GLContext* context);
 
-  // Used for explicit buffer management.  Expect buffers to be destroyed only
-  // when surface is not visible.
-  enum BufferAllocationState {
-    BUFFER_ALLOCATION_FRONT_AND_BACK,
-    BUFFER_ALLOCATION_FRONT_ONLY,
-    BUFFER_ALLOCATION_NONE
-  };
-  virtual void SetBufferAllocation(BufferAllocationState state);
+  // Used for explicit buffer management.
+  virtual void SetBackbufferAllocation(bool allocated);
+  virtual void SetFrontbufferAllocation(bool allocated);
 
   // Get a handle used to share the surface with another process. Returns null
   // if this is not possible.
   virtual void* GetShareHandle();
 
   // Get the platform specific display on which this surface resides, if
   // available.
   virtual void* GetDisplay();
 
   // Get the platfrom specific configuration for this surface, if available.
@@ skipping 35 matching lines @@
   virtual void Destroy() OVERRIDE;
   virtual bool Resize(const gfx::Size& size) OVERRIDE;
   virtual bool IsOffscreen() OVERRIDE;
   virtual bool SwapBuffers() OVERRIDE;
   virtual bool PostSubBuffer(int x, int y, int width, int height) OVERRIDE;
   virtual std::string GetExtensions() OVERRIDE;
   virtual gfx::Size GetSize() OVERRIDE;
   virtual void* GetHandle() OVERRIDE;
   virtual unsigned int GetBackingFrameBufferObject() OVERRIDE;
   virtual bool OnMakeCurrent(GLContext* context) OVERRIDE;
-  virtual void SetBufferAllocation(BufferAllocationState state) OVERRIDE;
+  virtual void SetBackbufferAllocation(bool allocated) OVERRIDE;
+  virtual void SetFrontbufferAllocation(bool allocated) OVERRIDE;
   virtual void* GetShareHandle() OVERRIDE;
   virtual void* GetDisplay() OVERRIDE;
   virtual void* GetConfig() OVERRIDE;
   virtual unsigned GetFormat() OVERRIDE;
 
   GLSurface* surface() const { return surface_.get(); }
 
  protected:
   virtual ~GLSurfaceAdapter();
 
  private:
   scoped_refptr<GLSurface> surface_;
   DISALLOW_COPY_AND_ASSIGN(GLSurfaceAdapter);
 };
 
 }  // namespace gfx
 
 #endif  // UI_GFX_GL_GL_SURFACE_H_