Remove unused entry point rateLimitOffscreenContextCHROMIUM from WebGraphicsContext3D

public/platform/WebGraphicsContext3D.h

 /*
  * Copyright (C) 2012 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 177 matching lines @@
     virtual void unmapTexSubImage2DCHROMIUM(const void*) = 0;
 
     // GL_CHROMIUM_request_extension
     virtual WebString getRequestableExtensionsCHROMIUM() = 0;
     virtual void requestExtensionCHROMIUM(const char*) = 0;
 
     // GL_CHROMIUM_framebuffer_multisample
     virtual void blitFramebufferCHROMIUM(WGC3Dint srcX0, WGC3Dint srcY0, WGC3Dint srcX1, WGC3Dint srcY1, WGC3Dint dstX0, WGC3Dint dstY0, WGC3Dint dstX1, WGC3Dint dstY1, WGC3Dbitfield mask, WGC3Denum filter) = 0;
     virtual void renderbufferStorageMultisampleCHROMIUM(WGC3Denum target, WGC3Dsizei samples, WGC3Denum internalformat, WGC3Dsizei width, WGC3Dsizei height) = 0;
 
-    // GL_CHROMIUM_rate_limit_offscreen_context
-    virtual void rateLimitOffscreenContextCHROMIUM() { }
-
     // GL_CHROMIUM_lose_context
     virtual void loseContextCHROMIUM(WGC3Denum current, WGC3Denum other) { }
 
     // The entry points below map directly to the OpenGL ES 2.0 API.
     // See: http://www.khronos.org/registry/gles/
     // and: http://www.khronos.org/opengles/sdk/docs/man/
     virtual void activeTexture(WGC3Denum texture) = 0;
     virtual void attachShader(WebGLId program, WebGLId shader) = 0;
     virtual void bindAttribLocation(WebGLId program, WGC3Duint index, const WGC3Dchar* name) = 0;
     virtual void bindBuffer(WGC3Denum target, WebGLId buffer) = 0;
@@ skipping 352 matching lines @@
     virtual void vertexAttribI4iv(WGC3Duint index, const WGC3Dint *v) { }
     virtual void vertexAttribI4ui(WGC3Duint index, WGC3Duint x, WGC3Duint y, WGC3Duint z, WGC3Duint w) { }
     virtual void vertexAttribI4uiv(WGC3Duint index, const WGC3Duint *v) { }
     virtual void vertexAttribIPointer(WGC3Duint index, WGC3Dint size, WGC3Denum type, WGC3Dsizei stride, WGC3Dintptr pointer) { }
     virtual void waitSync(WGC3Dsync sync, WGC3Dbitfield flags, WGC3Duint64 timeout) { }
 };
 
 } // namespace blink
 
 #endif