Unify var tracking between webkit and the proxy.

ppapi/shared_impl/tracker_base.h

Index: ppapi/shared_impl/tracker_base.h
===================================================================
--- ppapi/shared_impl/tracker_base.h	(revision 96002)
+++ ppapi/shared_impl/tracker_base.h	(working copy)
@@ -15,7 +15,7 @@
 
 class FunctionGroupBase;
 class ResourceObjectBase;
-class Var;
+class VarTracker;
 
 // Tracks resource and function APIs, providing a mapping between ID and
 // object.
@@ -50,16 +50,7 @@
   // resource is invalid.
   virtual PP_Instance GetInstanceForResource(PP_Resource resource) = 0;
 
-  // PP_Vars -------------------------------------------------------------------
-
-  // Adds a new var to the tracker, returning the new Var ID.
-  virtual int32 AddVar(Var* var) = 0;
-
-  // Retrieves a var from the tracker, returning an empty scoped ptr on failure.
-  virtual scoped_refptr<Var> GetVar(int32 var_id) const = 0;
-
-  virtual bool AddRefVar(int32 var_id) = 0;
-  virtual bool UnrefVar(int32 var_id) = 0;
+  virtual VarTracker* GetVarTracker() = 0;
 };
 
 }  // namespace ppapi