Refactor GL surface format handling

ui/gl/gl_surface_osmesa_win.h

 // Copyright 2016 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_GL_GL_SURFACE_OSMESA_WIN_H_
 #define UI_GL_GL_SURFACE_OSMESA_WIN_H_
 
 #include <dwmapi.h>
 
 #include "base/macros.h"
 #include "ui/gfx/native_widget_types.h"
 #include "ui/gl/gl_export.h"
 #include "ui/gl/gl_surface.h"
 #include "ui/gl/gl_surface_osmesa.h"
 
 namespace gl {
 
 // This OSMesa GL surface can use GDI to swap the contents of the buffer to a
 // view.
 class GL_EXPORT GLSurfaceOSMesaWin : public GLSurfaceOSMesa {
  public:
   explicit GLSurfaceOSMesaWin(gfx::AcceleratedWidget window);
 
   // Implement subset of GLSurface.
-  bool Initialize(GLSurface::Format format) override;
+  bool Initialize(GLSurfaceFormat format) override;
   void Destroy() override;
   bool IsOffscreen() override;
   gfx::SwapResult SwapBuffers() override;
   bool SupportsPostSubBuffer() override;
   gfx::SwapResult PostSubBuffer(int x, int y, int width, int height) override;
 
  private:
   ~GLSurfaceOSMesaWin() override;
 
   gfx::AcceleratedWidget window_;
   HDC device_context_;
 
   DISALLOW_COPY_AND_ASSIGN(GLSurfaceOSMesaWin);
 };
 
 }  // namespace gl
 
 #endif  // UI_GL_GL_SURFACE_OSMESA_WIN_H_