Merge 185069 "Enforce context refrence guards in WebGL extensions."

Source/core/html/canvas/ANGLEInstancedArrays.cpp

 /*
  * Copyright (C) 2013 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 50 matching lines @@
     return context->extensionsUtil()->supportsExtension("GL_ANGLE_instanced_arrays");
 }
 
 const char* ANGLEInstancedArrays::extensionName()
 {
     return "ANGLE_instanced_arrays";
 }
 
 void ANGLEInstancedArrays::drawArraysInstancedANGLE(GLenum mode, GLint first, GLsizei count, GLsizei primcount)
 {
-    if (isLost())
+    WebGLExtensionScopedContext scoped(this);
+    if (scoped.isLost())
         return;
 
-    m_context->drawArraysInstancedANGLE(mode, first, count, primcount);
+    scoped.context()->drawArraysInstancedANGLE(mode, first, count, primcount);
 }
 
 void ANGLEInstancedArrays::drawElementsInstancedANGLE(GLenum mode, GLsizei count, GLenum type, long long offset, GLsizei primcount)
 {
-    if (isLost())
+    WebGLExtensionScopedContext scoped(this);
+    if (scoped.isLost())
         return;
 
-    m_context->drawElementsInstancedANGLE(mode, count, type, offset, primcount);
+    scoped.context()->drawElementsInstancedANGLE(mode, count, type, offset, primcount);
 }
 
 void ANGLEInstancedArrays::vertexAttribDivisorANGLE(GLuint index, GLuint divisor)
 {
-    if (isLost())
+    WebGLExtensionScopedContext scoped(this);
+    if (scoped.isLost())
         return;
 
-    m_context->vertexAttribDivisorANGLE(index, divisor);
+    scoped.context()->vertexAttribDivisorANGLE(index, divisor);
 }
 
 } // namespace blink