Bug 1522246 - Shutdown workers immediately after terminate()ing them, r=asuth.

--HG--
extra : rebase_source : e4104b82f26fc80241b2d0f4f1bd096053ff9a5e

dom/workers/WorkerPrivate.cpp

@@ -2572,9 +2572,15 @@ void WorkerPrivate::DoRunLoop(JSContext* aCx) {
     {
       MutexAutoLock lock(mMutex);
 
+      // Wait for a runnable to arrive that we can execute, or for it to be okay
+      // to shutdown this worker once all holders have been removed.
+      // Holders may be removed from inside normal runnables, but we don't check
+      // for that after processing normal runnables, so we need to let control
+      // flow to the shutdown logic without blocking.
       while (mControlQueue.IsEmpty() &&
              !(debuggerRunnablesPending = !mDebuggerQueue.IsEmpty()) &&
-             !(normalRunnablesPending = NS_HasPendingEvents(mThread))) {
+             !(normalRunnablesPending = NS_HasPendingEvents(mThread)) &&
+             !(mStatus != Running && !HasActiveHolders())) {
         WaitForWorkerEvents();
       }