Convert the PluginResource to be refcounted.

ppapi/proxy/resource_creation_proxy.cc

Index: ppapi/proxy/resource_creation_proxy.cc
diff --git a/ppapi/proxy/resource_creation_proxy.cc b/ppapi/proxy/resource_creation_proxy.cc
index 18f481900dfe3a81a5cc8cf3ace6d94829fbcf93..596f7a58f29a069a18ef8946202135b5bb064868 100644
--- a/ppapi/proxy/resource_creation_proxy.cc
+++ b/ppapi/proxy/resource_creation_proxy.cc
@@ -158,9 +158,8 @@ PP_Resource ResourceCreationProxy::CreateFontObject(
   if (!ppapi::FontImpl::IsPPFontDescriptionValid(*description))
     return 0;
 
-  linked_ptr<Font> object(new Font(HostResource::MakeInstanceOnly(instance),
-                                   *description));
-  return PluginResourceTracker::GetInstance()->AddResource(object);
+  return PluginResourceTracker::GetInstance()->AddResource(
+      new Font(HostResource::MakeInstanceOnly(instance), *description));
 }
 
 PP_Resource ResourceCreationProxy::CreateGraphics2D(PP_Instance instance,
@@ -192,8 +191,8 @@ PP_Resource ResourceCreationProxy::CreateImageData(PP_Instance instance,
   PP_ImageDataDesc desc;
   memcpy(&desc, image_data_desc.data(), sizeof(PP_ImageDataDesc));
 
-  linked_ptr<ImageData> object(new ImageData(result, desc, image_handle));
-  return PluginResourceTracker::GetInstance()->AddResource(object);
+  return PluginResourceTracker::GetInstance()->AddResource(
+      new ImageData(result, desc, image_handle));
 }
 
 PP_Resource ResourceCreationProxy::CreateKeyboardInputEvent(