Cleanup: Remove unneeded forward declarations in ppapi.

ppapi/proxy/plugin_dispatcher.h

 // 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.
 
 #ifndef PPAPI_PROXY_PLUGIN_DISPATCHER_H_
 #define PPAPI_PROXY_PLUGIN_DISPATCHER_H_
 
+#include <set>
 #include <string>
 
 #include "base/basictypes.h"
 #include "base/hash_tables.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/process.h"
 #include "build/build_config.h"
 #include "ppapi/c/pp_rect.h"
 #include "ppapi/c/pp_instance.h"
 #include "ppapi/proxy/dispatcher.h"
 #include "ppapi/shared_impl/function_group_base.h"
 #include "ppapi/shared_impl/ppapi_preferences.h"
 
-class MessageLoop;
-
-namespace base {
-class WaitableEvent;
-}
-
 namespace ppapi {
 
 struct Preferences;
 class Resource;
+class WebKitForwarding;
 
 namespace proxy {
 
 // Used to keep track of per-instance data.
 struct InstanceData {
   InstanceData();
   ~InstanceData();
 
   PP_Rect position;
   PP_Bool fullscreen;  // Used for PPB_Fullscreen.
@@ skipping 134 matching lines @@
 
   uint32 plugin_dispatcher_id_;
 
   DISALLOW_COPY_AND_ASSIGN(PluginDispatcher);
 };
 
 }  // namespace proxy
 }  // namespace ppapi
 
 #endif  // PPAPI_PROXY_PLUGIN_DISPATCHER_H_