diff --git a/js/src/xpconnect/src/xpcwrappednative.cpp b/js/src/xpconnect/src/xpcwrappednative.cpp
--- a/js/src/xpconnect/src/xpcwrappednative.cpp
+++ b/js/src/xpconnect/src/xpcwrappednative.cpp
@@ -1187,16 +1187,19 @@ XPCWrappedNative::FinishInit(XPCCallCont
 #ifdef XPC_CHECK_WRAPPER_THREADSAFETY
     mThread = do_GetCurrentThread();
 
     if(HasProto() && GetProto()->ClassIsMainThreadOnly() && !NS_IsMainThread())
         DEBUG_ReportWrapperThreadSafetyError(ccx,
             "MainThread only wrapper created on the wrong thread", this);
 #endif
 
+    // A hack for bug 517665, increase the probability for GC.
+    ccx.GetJSContext()->updateMallocCounter(2 * sizeof(XPCWrappedNative));
+
     return JS_TRUE;
 }
 
 
 NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(XPCWrappedNative)
   NS_INTERFACE_MAP_ENTRY(nsIXPConnectWrappedNative)
   NS_INTERFACE_MAP_ENTRY(nsIXPConnectJSObjectHolder)
   NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, nsIXPConnectWrappedNative)