Relanding this with fixes to the mac dbg builder

webkit/plugins/ppapi/resource_helper.cc

 // Copyright (c) 2010 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 "webkit/plugins/ppapi/resource_helper.h"
 
 #include "base/logging.h"
 #include "ppapi/shared_impl/resource.h"
 #include "webkit/plugins/ppapi/host_globals.h"
 #include "webkit/plugins/ppapi/ppapi_plugin_instance.h"
 #include "webkit/plugins/ppapi/plugin_module.h"
 #include "webkit/plugins/ppapi/ppapi_plugin_instance.h"
 
 namespace webkit {
 namespace ppapi {
 
 // static
 PluginInstance* ResourceHelper::GetPluginInstance(
     const ::ppapi::Resource* resource) {
-  return HostGlobals::Get()->GetInstance(resource->pp_instance());
+  return PPInstanceToPluginInstance(resource->pp_instance());
+}
+
+PluginInstance* ResourceHelper::PPInstanceToPluginInstance(
+    PP_Instance instance) {
+  return HostGlobals::Get()->GetInstance(instance);
 }
 
 PluginModule* ResourceHelper::GetPluginModule(
     const ::ppapi::Resource* resource) {
   PluginInstance* instance = GetPluginInstance(resource);
   return instance ? instance->module() : NULL;
 }
 
 PluginDelegate* ResourceHelper::GetPluginDelegate(
     const ::ppapi::Resource* resource) {
   PluginInstance* instance = GetPluginInstance(resource);
   return instance ? instance->delegate() : NULL;
 }
 
 }  // namespace ppapi
 }  // namespace webkit