Add KHR_blend_equation_advanced

mojo/gpu/mojo_gles2_impl_autogen.cc

 // Copyright 2014 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.
 
 // This file is auto-generated from
 // gpu/command_buffer/build_gles2_cmd_buffer.py
 // It's formatted by clang-format using chromium coding style:
 //    clang-format -i -style=chromium filename
 // DO NOT EDIT!
 
@@ skipping 1566 matching lines @@
 void MojoGLES2Impl::SwapInterval(GLint interval) {
   NOTREACHED() << "Unimplemented SwapInterval.";
 }
 void MojoGLES2Impl::MatrixLoadfCHROMIUM(GLenum matrixMode, const GLfloat* m) {
   NOTREACHED() << "Unimplemented MatrixLoadfCHROMIUM.";
 }
 void MojoGLES2Impl::MatrixLoadIdentityCHROMIUM(GLenum matrixMode) {
   NOTREACHED() << "Unimplemented MatrixLoadIdentityCHROMIUM.";
 }
 void MojoGLES2Impl::BlendBarrierKHR() {
-  NOTREACHED() << "Unimplemented BlendBarrierKHR.";
+  MojoGLES2MakeCurrent(context_);
+  glBlendBarrierKHR();
 }
 
 }  // namespace mojo