[PPAPI] Added VarResource_Dev class.

ppapi/cpp/resource.h

 // Copyright (c) 2011 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_CPP_RESOURCE_H_
 #define PPAPI_CPP_RESOURCE_H_
 
 #include "ppapi/c/pp_resource.h"
 #include "ppapi/cpp/instance_handle.h"
 #include "ppapi/cpp/pass_ref.h"
 
 /// @file
 /// This file defines a <code>Resource</code> type representing data associated
 /// with the module.
 namespace pp {
 
+class VarResource_Dev;
+
 /// A reference counted module resource.
 class Resource {
  public:
   /// The default constructor.
   Resource();
 
   /// A constructor for copying a resource.
   ///
   /// @param[in] other A <code>Resource</code>.
   Resource(const Resource& other);
@@ skipping 47 matching lines @@
   /// The intended usage of this function that the derived class constructor
   /// will call the default <code>Resource</code> constructor, then make a call
   /// to create a resource. It then wants to assign the new resource (which,
   /// since it was returned by the browser, already had its reference count
   /// increased).
   ///
   /// @param[in] resource A <code>PP_Resource</code> corresponding to a
   /// resource.
   void PassRefFromConstructor(PP_Resource resource);
 
+  /// Sets this resource to null. This releases ownership of the resource.
+  void Clear();
+
  private:
+  friend class VarResource_Dev;
+
   PP_Resource pp_resource_;
 };
 
 }  // namespace pp
 
 inline bool operator==(const pp::Resource& lhs, const pp::Resource& rhs) {
   return lhs.pp_resource() == rhs.pp_resource();
 }
 
 inline bool operator!=(const pp::Resource& lhs, const pp::Resource& rhs) {
   return !(lhs == rhs);
 }
 
 #endif // PPAPI_CPP_RESOURCE_H_