Finish taking out render_messages.h include from other headers.

chrome/plugin/plugin_process.h

 // Copyright (c) 2006-2008 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 CHROME_PLUGIN_PLUGIN_PROCESS_H_
 #define CHROME_PLUGIN_PLUGIN_PROCESS_H_
 
+#include "base/file_path.h"
 #include "chrome/common/child_process.h"
 #include "chrome/plugin/plugin_thread.h"
 
 // Represents the plugin end of the renderer<->plugin connection. The
 // opposite end is the PluginProcessHost. This is a singleton object for
 // each plugin.
 class PluginProcess : public ChildProcess {
  public:
   static bool GlobalInit(const std::wstring& channel_name,
                          const FilePath& plugin_path);
@@ skipping 24 matching lines @@
 
   // The thread where plugin instances live.  Since NPAPI plugins weren't
   // created with multi-threading in mind, running multiple instances on
   // different threads would be asking for trouble.
   PluginThread plugin_thread_;
 
   DISALLOW_EVIL_CONSTRUCTORS(PluginProcess);
 };
 
 #endif  // CHROME_PLUGIN_PLUGIN_PROCESS_H_