Convert more interfaces to the new thunk system. This goes up to and including

ppapi/proxy/ppb_file_system_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_SYSTEM_PROXY_H_
 #define PPAPI_PROXY_PPB_FILE_SYSTEM_PROXY_H_
 
 #include <string>
 
 #include "base/basictypes.h"
+#include "ppapi/c/dev/ppb_file_system_dev.h"
 #include "ppapi/c/pp_instance.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_FileSystem_Dev;
 
 namespace pp {
 namespace proxy {
 
 class HostResource;
 
 class PPB_FileSystem_Proxy : public InterfaceProxy {
  public:
   PPB_FileSystem_Proxy(Dispatcher* dispatcher, const void* target_interface);
   virtual ~PPB_FileSystem_Proxy();
 
   static const Info* GetInfo();
 
-  const PPB_FileSystem_Dev* ppb_file_system_target() const {
-    return static_cast<const PPB_FileSystem_Dev*>(target_interface());
-  }
+  static PP_Resource CreateProxyResource(PP_Instance instance,
+                                         PP_FileSystemType_Dev type);
 
   // InterfaceProxy implementation.
   virtual bool OnMessageReceived(const IPC::Message& msg);
 
  private:
   // Message handlers.
   void OnMsgCreate(PP_Instance instance,
                    int type,
                    HostResource* result);
   void OnMsgOpen(const HostResource& filesystem,
                  int64_t expected_size);
 
   void OnMsgOpenComplete(const HostResource& filesystem,
                          int32_t result);
 
   void OpenCompleteInHost(int32_t result, const HostResource& host_resource);
 
   CompletionCallbackFactory<PPB_FileSystem_Proxy,
                             ProxyNonThreadSafeRefCount> callback_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(PPB_FileSystem_Proxy);
 };
 
 }  // namespace proxy
 }  // namespace pp
 
 #endif  // PPAPI_PROXY_PPB_FILE_SYSTEM_PROXY_H_