PPAPI: Never re-enter JavaScript for PostMessage.

content/renderer/pepper/pepper_hung_plugin_filter.h

 // Copyright (c) 2012 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_RENDERER_PEPPER_PEPPER_HUNG_PLUGIN_FILTER_H_
 #define CONTENT_RENDERER_PEPPER_PEPPER_HUNG_PLUGIN_FILTER_H_
 
 #include "base/files/file_path.h"
 #include "base/memory/ref_counted.h"
 #include "base/message_loop/message_loop_proxy.h"
 #include "base/synchronization/lock.h"
 #include "ipc/ipc_channel_proxy.h"
 #include "ipc/ipc_sync_message_filter.h"
 #include "ppapi/proxy/host_dispatcher.h"
 
 namespace content {
 
 // This class monitors a renderer <-> pepper plugin channel on the I/O thread
 // of the renderer for a hung plugin.
 //
 // If the plugin is not responding to sync messages, it will notify the browser
 // process and give the user the option to kill the hung plugin.
 //
 // Note that this class must be threadsafe since it will get the begin/end
 // block notifications on the main thread, but the filter is run on the I/O
 // thread. This is important since when we're blocked on a sync message to a
 // hung plugin, the main thread is frozen.
 //
-// NOTE: This class is refcounted (via SyncMessageStatusReceiver).
+// NOTE: This class is refcounted (via IPC::MessageFilter).
 class PepperHungPluginFilter
-    : public ppapi::proxy::HostDispatcher::SyncMessageStatusReceiver {
+    : public ppapi::proxy::HostDispatcher::SyncMessageStatusObserver,
+      public IPC::MessageFilter {
  public:
   // The |frame_routing_id| is the ID of the render_frame so that this class can
   // send messages to the browser via that frame's route. The |plugin_child_id|
   // is the ID in the browser process of the pepper plugin process host. We use
   // this to identify the proper plugin process to terminate.
   PepperHungPluginFilter(const base::FilePath& plugin_path,
                          int frame_routing_id,
                          int plugin_child_id);
 
   // SyncMessageStatusReceiver implementation.
@@ skipping 63 matching lines @@
   bool hung_plugin_showing_;
 
   bool timer_task_pending_;
 
   DISALLOW_COPY_AND_ASSIGN(PepperHungPluginFilter);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_PEPPER_PEPPER_HUNG_PLUGIN_FILTER_H_