Browser Plugin: Implement BrowserPluginObserver.

content/public/renderer/browser_plugin/browser_plugin_observer.h

+// Copyright (c) 2013 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.
+
+#ifndef CONTENT_PUBLIC_RENDERER_BROWSER_PLUGIN_BROWSER_PLUGIN_OBSERVER_H_
+#define CONTENT_PUBLIC_RENDERER_BROWSER_PLUGIN_BROWSER_PLUGIN_OBSERVER_H_
+
+#include "base/compiler_specific.h"
+#include "content/common/content_export.h"
+#include "ipc/ipc_listener.h"
+#include "ipc/ipc_sender.h"
+
+namespace content {
+
+class BrowserPlugin;
+class BrowserPluginImpl;
+
+// Base class for objects that want to filter incoming IPCs.
+// A BrowserPluginObserver attaches itself to a particular BrowserPlugin.
+// By default, its lifetime is tied to the BrowserPlugin's lifetime.
+class CONTENT_EXPORT BrowserPluginObserver : public IPC::Listener,
+                                             public IPC::Sender {
+ public:
+  BrowserPlugin* browser_plugin() const;
+
+  // By default, observers will be deleted when the BrowserPlugin goes away.  If
+  // they want to outlive it, they can override this function.
+  virtual void OnDestruct();
+
+  // IPC::Listener implementation.
+  virtual bool OnMessageReceived(const IPC::Message& message) OVERRIDE;
+
+  // IPC::Sender implementation.
+  virtual bool Send(IPC::Message* message) OVERRIDE;
+
+ protected:
+  explicit BrowserPluginObserver(BrowserPlugin* browser_plugin);
+  virtual ~BrowserPluginObserver();
+
+  friend class BrowserPluginImpl;
+
+  // This is called by the BrowserPlugin when it's going away so that this
+  // object can null out its pointer.
+  void BrowserPluginGone();
+
+  BrowserPlugin* browser_plugin_;
+
+  DISALLOW_COPY_AND_ASSIGN(BrowserPluginObserver);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_PUBLIC_RENDERER_BROWSER_PLUGIN_BROWSER_PLUGIN_OBSERVER_H_