mojo: Add a runloop utility in python

mojo/python/tests/runloop_unittest.py

+# Copyright 2014 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import unittest
+
+# pylint: disable=F0401
+import mojo.embedder
+from mojo import system
+
+class RunLoopTest(unittest.TestCase):
+
+  def setUp(self):
+    mojo.embedder.Init()
+
+  def testRunLoop(self):
+    loop = system.RunLoop()
+    array = []
+    def Increment():
+      array.append(0)
+    for _ in xrange(10):
+      loop.PostDelayedTask(Increment)
+    loop.RunUntilIdle()
+    self.assertEquals(len(array), 10)