Implement WEBGL_shared_resources

Source/core/html/canvas/WebGLRenderingContext.idl

 /*
  * Copyright (C) 2009 Apple 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
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 389 matching lines @@
     const GLenum LOW_FLOAT                      = 0x8DF0;
     const GLenum MEDIUM_FLOAT                   = 0x8DF1;
     const GLenum HIGH_FLOAT                     = 0x8DF2;
     const GLenum LOW_INT                        = 0x8DF3;
     const GLenum MEDIUM_INT                     = 0x8DF4;
     const GLenum HIGH_INT                       = 0x8DF5;
 
     /* Framebuffer Object. */
     const GLenum FRAMEBUFFER                    = 0x8D40;
     const GLenum RENDERBUFFER                   = 0x8D41;
+    const GLenum READ_FRAMEBUFFER               = 0x8CA8;
+    const GLenum DRAW_FRAMEBUFFER               = 0x8CA9;
 
     const GLenum RGBA4                          = 0x8056;
     const GLenum RGB5_A1                        = 0x8057;
     const GLenum RGB565                         = 0x8D62;
     const GLenum DEPTH_COMPONENT16              = 0x81A5;
     const GLenum STENCIL_INDEX                  = 0x1901;
     const GLenum STENCIL_INDEX8                 = 0x8D48;
     const GLenum DEPTH_STENCIL                  = 0x84F9;
 
     const GLenum RENDERBUFFER_WIDTH             = 0x8D42;
@@ skipping 233 matching lines @@
     [StrictTypeChecking, Custom] void vertexAttrib2fv(GLuint indx, Float32Array values);
     [StrictTypeChecking] void         vertexAttrib3f(GLuint indx, GLfloat x, GLfloat y, GLfloat z);
     [StrictTypeChecking, Custom] void vertexAttrib3fv(GLuint indx, Float32Array values);
     [StrictTypeChecking] void         vertexAttrib4f(GLuint indx, GLfloat x, GLfloat y, GLfloat z, GLfloat w);
     [StrictTypeChecking, Custom] void vertexAttrib4fv(GLuint indx, Float32Array values);
     [StrictTypeChecking, RaisesException] void         vertexAttribPointer(GLuint indx, GLint size, GLenum type, GLboolean normalized, 
                                                           GLsizei stride, GLintptr offset);
 
     [StrictTypeChecking] void         viewport(GLint x, GLint y, GLsizei width, GLsizei height);
 };