[PPAPI] Added VarResource_Dev class.

ppapi/cpp/resource.h

Index: ppapi/cpp/resource.h
diff --git a/ppapi/cpp/resource.h b/ppapi/cpp/resource.h
index 8f5a92d2e1214815bd1762800fe39ae1b396739d..311db6a1caf4b005f5c94b6a23f93466119acb94 100644
--- a/ppapi/cpp/resource.h
+++ b/ppapi/cpp/resource.h
@@ -14,6 +14,8 @@
 /// with the module.
 namespace pp {
 
+class VarResource_Dev;
+
 /// A reference counted module resource.
 class Resource {
  public:
@@ -81,7 +83,12 @@ class Resource {
   /// 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_;
 };