iwyu: Use callback_old.h where appropriate, part 1.

webkit/plugins/ppapi/plugin_delegate.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 WEBKIT_PLUGINS_PPAPI_PLUGIN_DELEGATE_H_
 #define WEBKIT_PLUGINS_PPAPI_PLUGIN_DELEGATE_H_
 
 #include <string>
 
-#include "base/callback.h"
+#include "base/callback_old.h"
 #include "base/message_loop_proxy.h"
 #include "base/memory/ref_counted.h"
 #include "base/platform_file.h"
 #include "base/shared_memory.h"
 #include "base/sync_socket.h"
 #include "base/time.h"
 #include "googleurl/src/gurl.h"
 #include "media/video/video_decode_accelerator.h"
 #include "ppapi/c/pp_completion_callback.h"
 #include "ppapi/c/pp_errors.h"
@@ skipping 372 matching lines @@
 
   // TODO(viettrungluu): Generalize this for use with other plugins if it proves
   // necessary.
   virtual std::string GetFlashCommandLineArgs() = 0;
 };
 
 }  // namespace ppapi
 }  // namespace webkit
 
 #endif  // WEBKIT_PLUGINS_PPAPI_PLUGIN_DELEGATE_H_