Bug 1248719. Fix things so that taking ownership of error reporting on an AutoJSAPI on a worker is OK even if that AutoJSAPI was initialized without an explicit global. r=bholley

dom/base/ScriptSettings.cpp

@@ -507,8 +507,13 @@ AutoJSAPI::ReportException()
   // In this case, we enter the privileged junk scope and don't dispatch any
   // error events.
   JS::Rooted<JSObject*> errorGlobal(cx(), JS::CurrentGlobalOrNull(cx()));
-  if (!errorGlobal)
-    errorGlobal = xpc::PrivilegedJunkScope();
+  if (!errorGlobal) {
+    if (mIsMainThread) {
+      errorGlobal = xpc::PrivilegedJunkScope();
+    } else {
+      errorGlobal = workers::GetCurrentThreadWorkerGlobal();
+    }
+  }
   JSAutoCompartment ac(cx(), errorGlobal);
   JS::Rooted<JS::Value> exn(cx());
   js::ErrorReport jsReport(cx());

dom/bindings/BindingUtils.cpp

@@ -3247,8 +3247,7 @@ UnprivilegedJunkScopeOrWorkerGlobal()
     return xpc::UnprivilegedJunkScope();
   }
 
-  return workers::GetCurrentThreadWorkerPrivate()->
-    GlobalScope()->GetGlobalJSObject();
+  return workers::GetCurrentThreadWorkerGlobal();
 }
 } // namespace binding_detail
 

dom/workers/RuntimeService.cpp

@@ -1369,6 +1369,12 @@ GetCurrentThreadJSContext()
   return GetCurrentThreadWorkerPrivate()->GetJSContext();
 }
 
+JSObject*
+GetCurrentThreadWorkerGlobal()
+{
+  return GetCurrentThreadWorkerPrivate()->GlobalScope()->GetGlobalJSObject();
+}
+
 END_WORKERS_NAMESPACE
 
 struct RuntimeService::IdleThreadInfo

dom/workers/WorkerPrivate.h

@@ -1446,6 +1446,9 @@ IsCurrentThreadRunningChromeWorker();
 JSContext*
 GetCurrentThreadJSContext();
 
+JSObject*
+GetCurrentThreadWorkerGlobal();
+
 class AutoSyncLoopHolder
 {
   WorkerPrivate* mWorkerPrivate;