Bug 784730 - Crash in ReparentWrapperIfFound if wrapper already in scope. r=bholley

js/xpconnect/src/XPCMaps.h

@@ -107,6 +107,7 @@ public:
     {
         NS_PRECONDITION(wrapper,"bad param");
         nsISupports* obj = wrapper->GetIdentityObject();
+        MOZ_ASSERT(!Find(obj), "wrapper already in new scope!");
         Entry* entry = (Entry*)
             JS_DHashTableOperate(mTable, obj, JS_DHASH_ADD);
         if (!entry)

js/xpconnect/src/XPCWrappedNative.cpp

@@ -1582,8 +1582,8 @@ XPCWrappedNative::ReparentWrapperIfFound(XPCCallContext& ccx,
                     wrapper->UpdateScriptableInfo(newProto->GetScriptableInfo());
                 }
 
-                NS_ASSERTION(!newMap->Find(wrapper->GetIdentityObject()),
-                             "wrapper already in new scope!");
+                if (newMap->Find(wrapper->GetIdentityObject()))
+                    MOZ_CRASH();
 
                 if (!newMap->Add(wrapper))
                     MOZ_CRASH();