Make -Wshadow happy.

LOG=y
BUG=v8:3073
R=bmeurer@chromium.org

Review URL: https://codereview.chromium.org/119983003

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@18463 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

include/v8.h

@@ -738,7 +738,7 @@ template <class T, class M> class Persistent : public PersistentBase<T> {
 template<class T>
 class UniquePersistent : public PersistentBase<T> {
   struct RValue {
-    V8_INLINE explicit RValue(UniquePersistent* object) : object(object) {}
+    V8_INLINE explicit RValue(UniquePersistent* obj) : object(obj) {}
     UniquePersistent* object;
   };