Bug 1361709 - Move FlushPendingLinkUpdatesFromRunnable to idle dispatch; r=smaug

dom/base/nsDocument.cpp

@@ -10010,9 +10010,9 @@ nsIDocument::RegisterPendingLinkUpdate(Link* aLink)
   if (!mHasLinksToUpdateRunnable) {
     nsCOMPtr<nsIRunnable> event =
       NewRunnableMethod(this, &nsIDocument::FlushPendingLinkUpdatesFromRunnable);
+    // Do this work in a second in the worst case.
     nsresult rv =
-      Dispatch("nsIDocument::FlushPendingLinkUpdatesFromRunnable",
-               TaskCategory::Other, event.forget());
+      NS_IdleDispatchToCurrentThread(event.forget(), 1000);
     if (NS_FAILED(rv)) {
       // If during shutdown posting a runnable doesn't succeed, we probably
       // don't need to update link states.