[PPAPI] ResourceVar now reference counts its PP_Resource in the plugin.

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_->pp_resource();
+}
+
+bool PluginResourceVar::IsPending() const {
+  return false;
+}
+
+PluginResourceVar::~PluginResourceVar() {}