Add GL_CHROMIUM_screen_space_antialiasing to support alternative AA

gpu/command_buffer/client/gles2_implementation_impl_autogen.h

 // 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 3640 matching lines @@
 }
 
 void GLES2Implementation::BlendBarrierKHR() {
   GPU_CLIENT_SINGLE_THREAD_CHECK();
   GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glBlendBarrierKHR("
                      << ")");
   helper_->BlendBarrierKHR();
   CheckGLError();
 }
 
+void GLES2Implementation::ApplyScreenSpaceAntialiasingCHROMIUM() {
+  GPU_CLIENT_SINGLE_THREAD_CHECK();
+  GPU_CLIENT_LOG("[" << GetLogPrefix()
+                     << "] glApplyScreenSpaceAntialiasingCHROMIUM("
+                     << ")");
+  helper_->ApplyScreenSpaceAntialiasingCHROMIUM();
+  CheckGLError();
+}
+
 #endif  // GPU_COMMAND_BUFFER_CLIENT_GLES2_IMPLEMENTATION_IMPL_AUTOGEN_H_