Remove implicit conversions from scoped_refptr to T* in ppapi/

ppapi/proxy/plugin_resource_var.cc

 // Copyright 2013 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/plugin_resource_var.h"
 
 PluginResourceVar::PluginResourceVar() {}
 
 PluginResourceVar::PluginResourceVar(ppapi::Resource* resource)
     : resource_(resource) {}
 
 PP_Resource PluginResourceVar::GetPPResource() const {
-  return resource_ ? resource_->pp_resource() : 0;
+  return resource_.get() ? resource_->pp_resource() : 0;
 }
 
 bool PluginResourceVar::IsPending() const {
   return false;
 }
 
 PluginResourceVar::~PluginResourceVar() {}