1 files changed, 9 insertions, 4 deletions
diff --git a/dom/workers/WorkerRunnable.cpp b/dom/workers/WorkerRunnable.cpp
index 1e16d7254..6bbe40f66 100644
--- a/dom/workers/WorkerRunnable.cpp
+++ b/dom/workers/WorkerRunnable.cpp
@@ -568,15 +568,20 @@ WorkerMainThreadRunnable::WorkerMainThreadRunnable(WorkerPrivate* aWorkerPrivate
 }
 
 void
-WorkerMainThreadRunnable::Dispatch(ErrorResult& aRv)
+WorkerMainThreadRunnable::Dispatch(Status aFailStatus, ErrorResult& aRv)
 {
   mWorkerPrivate->AssertIsOnWorkerThread();
 
   TimeStamp startTime = TimeStamp::NowLoRes();
 
-  AutoSyncLoopHolder syncLoop(mWorkerPrivate);
+  AutoSyncLoopHolder syncLoop(mWorkerPrivate, aFailStatus);
 
-  mSyncLoopTarget = syncLoop.EventTarget();
+  mSyncLoopTarget = syncLoop.GetEventTarget();
+  if (!mSyncLoopTarget) {
+    // SyncLoop creation can fail if the worker is shutting down.
+    aRv.Throw(NS_ERROR_DOM_INVALID_STATE_ERR);
+    return;
+  }
 
   DebugOnly<nsresult> rv = mWorkerPrivate->DispatchToMainThread(this);
   MOZ_ASSERT(NS_SUCCEEDED(rv),
@@ -621,7 +626,7 @@ bool
 WorkerCheckAPIExposureOnMainThreadRunnable::Dispatch()
 {
   ErrorResult rv;
-  WorkerMainThreadRunnable::Dispatch(rv);
+  WorkerMainThreadRunnable::Dispatch(Terminating, rv);
   bool ok = !rv.Failed();
   rv.SuppressException();
   return ok;