Make a global enum to differentiate impl & proxy.

ppapi/proxy/ppb_file_ref_proxy.cc

 // 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.
 
 #include "ppapi/proxy/ppb_file_ref_proxy.h"
 
 #include <map>
 
 #include "base/bind.h"
 #include "ppapi/c/pp_errors.h"
@@ skipping 58 matching lines @@
   // the callback will be identified when it's passed to the host and then
   // back here.
   int next_callback_id_;
   typedef std::map<int, scoped_refptr<TrackedCallback> > PendingCallbackMap;
   PendingCallbackMap pending_callbacks_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(FileRef);
 };
 
 FileRef::FileRef(const PPB_FileRef_CreateInfo& info)
-    : PPB_FileRef_Shared(PPB_FileRef_Shared::InitAsProxy(), info),
+    : PPB_FileRef_Shared(OBJECT_IS_PROXY, info),
       next_callback_id_(1) {
 }
 
 FileRef::~FileRef() {
   // The callbacks map should have been cleared by LastPluginRefWasDeleted.
   DCHECK(pending_callbacks_.empty());
 }
 
 void FileRef::LastPluginRefWasDeleted() {
   // The callback tracker will abort our callbacks for us.
@@ skipping 247 matching lines @@
     int32_t result,
     const HostResource& host_resource,
     int callback_id) {
   // Execute OnMsgCallbackComplete in the plugin process.
   Send(new PpapiMsg_PPBFileRef_CallbackComplete(
       API_ID_PPB_FILE_REF, host_resource, callback_id, result));
 }
 
 }  // namespace proxy
 }  // namespace ppapi