workerpool: Export function to check for running tasks

Signed-off-by: Michael Hanselmann <hansmi@google.com>
Reviewed-by: Iustin Pop <iustin@google.com>

lib/workerpool.py

@@ -412,6 +412,16 @@ class WorkerPool(object):
         return True
     return False
 
+  def HasRunningTasks(self):
+    """Checks whether there's at least one task running.
+
+    """
+    self._lock.acquire()
+    try:
+      return self._HasRunningTasksUnlocked()
+    finally:
+      self._lock.release()
+
   def Quiesce(self):
     """Waits until the task queue is empty.