Add a RenderProcessObserver. For now this will be primarily used to filter control messages, so ...

content/renderer/render_process_observer.cc

+// Copyright (c) 2011 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.
+
+#include "content/renderer/render_process_observer.h"
+
+RenderProcessObserver::~RenderProcessObserver() {
+}
+
+bool RenderProcessObserver::OnControlMessageReceived(
+    const IPC::Message& message) {
+  return false;
+}
+
+void RenderProcessObserver::OnRenderProcessShutdown() {
+}