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

content/renderer/pepper/host_resource_var.h

+// 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.
+
+#ifndef PPAPI_CONTENT_RENDERER_PEPPER_HOST_RESOURCE_VAR_H_
+#define PPAPI_CONTENT_RENDERER_PEPPER_HOST_RESOURCE_VAR_H_
+
+#include "base/memory/scoped_ptr.h"
+#include "ipc/ipc_message.h"
+#include "ppapi/c/pp_resource.h"
+#include "ppapi/shared_impl/resource_var.h"
+#include "ppapi/shared_impl/var.h"
+
+namespace content {
+
+// Represents a resource var, usable on the host side. Can either have a
+// plugin-side resource or a pending resource host.
+class HostResourceVar : public ppapi::ResourceVar {
+ public:
+  // Makes a null resource var.
+  HostResourceVar();
+
+  // Makes a resource var with an existing plugin-side resource.
+  explicit HostResourceVar(PP_Resource pp_resource);
+
+  // Makes a resource var with a pending resource host.
+  // The |creation_message| contains data needed to create the plugin-side
+  // resource. Its type depends on the type of resource.
+  explicit HostResourceVar(const IPC::Message& creation_message);
+
+  // ResourceVar override.
+  virtual PP_Resource GetPPResource() const OVERRIDE;
+  virtual const IPC::Message* GetCreationMessage() const OVERRIDE;
+  virtual bool IsPending() const OVERRIDE;
+
+ protected:
+  virtual ~HostResourceVar();
+
+ private:
+  // Real resource ID in the plugin. 0 if one has not yet been created
+  // (indicating that there is a pending host resource).
+  PP_Resource pp_resource_;
+
+  // If the plugin-side resource has not yet been created, carries a message to
+  // create a resource of the specific type on the plugin side. Otherwise, NULL.
+  scoped_ptr<IPC::Message> creation_message_;
+
+  DISALLOW_COPY_AND_ASSIGN(HostResourceVar);
+};
+
+}  // namespace content
+
+#endif