gpu: Remove WebGraphicsContext3D::makeContextCurrent() in Blink

Source/platform/graphics/test/MockWebGraphicsContext3D.h

 /*
  * Copyright (C) 2011 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 23 matching lines @@
 // WebGraphicsContext3D base class for use in WebKit unit tests.
 // All operations are no-ops (returning 0 if necessary).
 class MockWebGraphicsContext3D : public WebGraphicsContext3D {
 public:
     MockWebGraphicsContext3D()
         : m_nextTextureId(1)
         , m_contextLost(false)
     {
     }
 
-    virtual bool makeContextCurrent() { return true; }
-
     virtual void prepareTexture() { }
 
     virtual void postSubBufferCHROMIUM(int x, int y, int width, int height) { }
 
     virtual void synthesizeGLError(WGC3Denum) { }
 
     virtual bool isContextLost() { return m_contextLost; }
 
     virtual void* mapBufferSubDataCHROMIUM(WGC3Denum target, WGC3Dintptr offset, WGC3Dsizeiptr size, WGC3Denum access) { return 0; }
     virtual void unmapBufferSubDataCHROMIUM(const void*) { }
@@ skipping 234 matching lines @@
     void fakeContextLost() { m_contextLost = true; }
 protected:
     unsigned m_nextTextureId;
     bool m_contextLost;
     Attributes m_attrs;
 };
 
 } // namespace blink
 
 #endif // MockWebGraphicsContext3D_h