Add GL_CHROMIUM_screen_space_antialiasing to support alternative AA

gpu/command_buffer/client/gles2_cmd_helper_autogen.h

Index: gpu/command_buffer/client/gles2_cmd_helper_autogen.h
diff --git a/gpu/command_buffer/client/gles2_cmd_helper_autogen.h b/gpu/command_buffer/client/gles2_cmd_helper_autogen.h
index d31d0d85d8b0dbffe9bdc7a66b64a8190615edc1..fb77fa29a5b867a9350ed8442769055ab7fd10aa 100644
--- a/gpu/command_buffer/client/gles2_cmd_helper_autogen.h
+++ b/gpu/command_buffer/client/gles2_cmd_helper_autogen.h
@@ -2955,4 +2955,12 @@ void BlendBarrierKHR() {
   }
 }
 
+void ApplyScreenSpaceAntialiasingCHROMIUM() {
+  gles2::cmds::ApplyScreenSpaceAntialiasingCHROMIUM* c =
+      GetCmdSpace<gles2::cmds::ApplyScreenSpaceAntialiasingCHROMIUM>();
+  if (c) {
+    c->Init();
+  }
+}
+
 #endif  // GPU_COMMAND_BUFFER_CLIENT_GLES2_CMD_HELPER_AUTOGEN_H_