Convert utility process extension ParseUpdate IPC to mojo

extensions/shell/utility/shell_content_utility_client.h

Index: extensions/shell/utility/shell_content_utility_client.h
diff --git a/extensions/shell/utility/shell_content_utility_client.h b/extensions/shell/utility/shell_content_utility_client.h
index c98742733c2731e9020d03b20b6bd3a8f3be2a58..4baaf1752f162c2fc08fec85ad695eb278ab10eb 100644
--- a/extensions/shell/utility/shell_content_utility_client.h
+++ b/extensions/shell/utility/shell_content_utility_client.h
@@ -17,10 +17,6 @@ class ShellContentUtilityClient : public content::ContentUtilityClient {
 
   // content::ContentUtilityClient:
   void UtilityThreadStarted() override;
-  bool OnMessageReceived(const IPC::Message& message) override;
-
- private:
-  UtilityHandler utility_handler_;
 };
 
 }  // namespace extensions