Bug 958780 - B2G Crash during FTU. r=smaug

dom/base/nsGlobalWindow.cpp

@@ -1763,7 +1763,10 @@ NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(nsGlobalWindow)
   }
   NS_IMPL_CYCLE_COLLECTION_UNLINK(mLocalStorage)
   NS_IMPL_CYCLE_COLLECTION_UNLINK(mSessionStorage)
-  NS_IMPL_CYCLE_COLLECTION_UNLINK(mApplicationCache)
+  if (tmp->mApplicationCache) {
+    static_cast<nsDOMOfflineResourceList*>(tmp->mApplicationCache.get())->Disconnect();
+    NS_IMPL_CYCLE_COLLECTION_UNLINK(mApplicationCache)
+  }
   NS_IMPL_CYCLE_COLLECTION_UNLINK(mDocumentPrincipal)
   NS_IMPL_CYCLE_COLLECTION_UNLINK(mDoc)
   NS_IMPL_CYCLE_COLLECTION_UNLINK(mIdleService)