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 249e8a465ace6faa60e195f4553cfa530dc6487c..daea67c29577b8f8b89d545e20be228b6aa8516e 100644
--- a/gpu/command_buffer/client/gles2_cmd_helper_autogen.h
+++ b/gpu/command_buffer/client/gles2_cmd_helper_autogen.h
@@ -3014,4 +3014,12 @@ void BlendBarrierKHR() {
   }
 }
 
+void ApplyScreenSpaceAntialiasing() {
+  gles2::cmds::ApplyScreenSpaceAntialiasing* c =
+      GetCmdSpace<gles2::cmds::ApplyScreenSpaceAntialiasing>();
+  if (c) {
+    c->Init();
+  }
+}
+
 #endif  // GPU_COMMAND_BUFFER_CLIENT_GLES2_CMD_HELPER_AUTOGEN_H_