Cleanup: Remove unneeded forward declarations in ppapi.

ppapi/proxy/ppb_file_ref_proxy.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_PPB_FILE_REF_PROXY_H_
 #define PPAPI_PROXY_PPB_FILE_REF_PROXY_H_
 
 #include <string>
 
 #include "base/basictypes.h"
 #include "ppapi/c/pp_module.h"
 #include "ppapi/c/pp_resource.h"
 #include "ppapi/c/pp_time.h"
 #include "ppapi/cpp/completion_callback.h"
 #include "ppapi/proxy/interface_proxy.h"
 #include "ppapi/proxy/proxy_non_thread_safe_ref_count.h"
 
-struct PPB_FileRef_Dev;
-
 namespace ppapi {
 
 class HostResource;
 struct PPB_FileRef_CreateInfo;
 
 namespace proxy {
 
 class PPB_FileRef_Proxy : public InterfaceProxy {
  public:
-  PPB_FileRef_Proxy(Dispatcher* dispatcher);
+  explicit PPB_FileRef_Proxy(Dispatcher* dispatcher);
   virtual ~PPB_FileRef_Proxy();
 
   static PP_Resource CreateProxyResource(PP_Resource file_system,
                                          const char* path);
 
   // InterfaceProxy implementation.
   virtual bool OnMessageReceived(const IPC::Message& msg);
 
   // Takes a resource in the host and converts it into a serialized file ref
   // "create info" for reconstitution in the plugin. This struct contains all
@@ skipping 51 matching lines @@
   pp::CompletionCallbackFactory<PPB_FileRef_Proxy,
                                 ProxyNonThreadSafeRefCount> callback_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(PPB_FileRef_Proxy);
 };
 
 }  // namespace proxy
 }  // namespace ppapi
 
 #endif  // PPAPI_PROXY_PPB_FILE_REF_PROXY_H_