Cleanup GpuMemoryManager and helpers.

ui/gl/gl_context_glx.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_GL_GL_CONTEXT_GLX_H_
 #define UI_GL_GL_CONTEXT_GLX_H_
 
 #include <string>
 
 #include "base/compiler_specific.h"
@@ skipping 14 matching lines @@
 
   // Implement GLContext.
   bool Initialize(GLSurface* compatible_surface,
                   GpuPreference gpu_preference) override;
   bool MakeCurrent(GLSurface* surface) override;
   void ReleaseCurrent(GLSurface* surface) override;
   bool IsCurrent(GLSurface* surface) override;
   void* GetHandle() override;
   void OnSetSwapInterval(int interval) override;
   std::string GetExtensions() override;
-  bool GetTotalGpuMemory(size_t* bytes) override;
   bool WasAllocatedUsingRobustnessExtension() override;
 
  protected:
   ~GLContextGLX() override;
 
  private:
   void Destroy();
 
   void* context_;
   XDisplay* display_;
 
   DISALLOW_COPY_AND_ASSIGN(GLContextGLX);
 };
 
 }  // namespace gfx
 
 #endif  // UI_GL_GL_CONTEXT_GLX_H_