Refactor BluetoothDispatcher to use CurrentWorkerId everywhere.

content/child/bluetooth/bluetooth_dispatcher.cc

Index: content/child/bluetooth/bluetooth_dispatcher.cc
diff --git a/content/child/bluetooth/bluetooth_dispatcher.cc b/content/child/bluetooth/bluetooth_dispatcher.cc
index 0bd7f2b97cd3e202fe28a5fe394b193ae443990a..77bd0c40696c6d0f02674c9b14d63a97e1990785 100644
--- a/content/child/bluetooth/bluetooth_dispatcher.cc
+++ b/content/child/bluetooth/bluetooth_dispatcher.cc
@@ -80,7 +80,7 @@ BluetoothDispatcher* BluetoothDispatcher::GetOrCreateThreadSpecificInstance(
     return g_dispatcher_tls.Pointer()->Get();
 
   BluetoothDispatcher* dispatcher = new BluetoothDispatcher(thread_safe_sender);
-  if (WorkerTaskRunner::Instance()->CurrentWorkerId())
+  if (CurrentWorkerId())
     WorkerTaskRunner::Instance()->AddStopObserver(dispatcher);
   return dispatcher;
 }