Revert r21117 as it caused reliability failures....

chrome/plugin/plugin_thread.h

Index: chrome/plugin/plugin_thread.h
===================================================================
--- chrome/plugin/plugin_thread.h	(revision 21215)
+++ chrome/plugin/plugin_thread.h	(working copy)
@@ -16,6 +16,8 @@
 #include "base/file_descriptor_posix.h"
 #endif
 
+class NotificationService;
+
 // The PluginThread class represents a background thread where plugin instances
 // live.  Communication occurs between WebPluginDelegateProxy in the renderer
 // process and WebPluginDelegateStub in this thread through IPC messages.
@@ -30,12 +32,18 @@
  private:
   virtual void OnControlMessageReceived(const IPC::Message& msg);
 
+  // Thread implementation:
+  virtual void Init();
+  virtual void CleanUp();
+
   // Callback for when a channel has been created.
   void OnCreateChannel(
       int process_id,
       bool off_the_record);
   void OnPluginMessage(const std::vector<uint8> &data);
 
+  scoped_ptr<NotificationService> notification_service_;
+
   // The plugin module which is preloaded in Init
   base::NativeLibrary preloaded_plugin_module_;