Fix navigation to unittest files

tools/telemetry/telemetry/page/actions/loop_unittest.py

 # Copyright 2013 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.
 
 from telemetry.core import util
 from telemetry.page.actions import loop
 from telemetry.unittest import tab_test_case
-from telemetry.unittest import test
 
 AUDIO_1_LOOP_CHECK = 'window.__hasEventCompleted("#audio_1", "loop");'
 VIDEO_1_LOOP_CHECK = 'window.__hasEventCompleted("#video_1", "loop");'
 
 
 class LoopActionTest(tab_test_case.TabTestCase):
 
   def setUp(self):
     tab_test_case.TabTestCase.setUp(self)
-    self._browser.SetHTTPServerDirectories(util.GetUnittestDataDir())
-    self._tab.Navigate(self._browser.http_server.UrlOf('video_test.html'))
-    self._tab.WaitForDocumentReadyStateToBeComplete()
+    self.Navigate('video_test.html')
 
-  @test.Disabled('chromeos')
   def testLoopWithNoSelector(self):
     """Tests that with no selector Loop action loops first media element."""
     data = {'selector': '#video_1', 'loop_count': 2}
     action = loop.LoopAction(data)
     action.WillRunAction(None, self._tab)
     action.RunAction(None, self._tab, None)
     # Assert only first video has played.
     self.assertTrue(self._tab.EvaluateJavaScript(VIDEO_1_LOOP_CHECK))
     self.assertFalse(self._tab.EvaluateJavaScript(AUDIO_1_LOOP_CHECK))
 
-  @test.Disabled('chromeos')
   def testLoopWithAllSelector(self):
     """Tests that Loop action loops all video elements with selector='all'."""
     data = {'selector': 'all', 'loop_count': 2}
     action = loop.LoopAction(data)
     action.WillRunAction(None, self._tab)
     # Both videos not playing before running action.
     self.assertFalse(self._tab.EvaluateJavaScript(VIDEO_1_LOOP_CHECK))
     self.assertFalse(self._tab.EvaluateJavaScript(AUDIO_1_LOOP_CHECK))
     action.RunAction(None, self._tab, None)
     # Assert all media elements played.
     self.assertTrue(self._tab.EvaluateJavaScript(VIDEO_1_LOOP_CHECK))
     self.assertTrue(self._tab.EvaluateJavaScript(AUDIO_1_LOOP_CHECK))
 
-  @test.Disabled('chromeos')
   def testLoopWaitForLoopTimeout(self):
     """Tests that wait_for_loop timeouts if video does not loop."""
     data = {'selector': '#video_1',
             'wait_timeout': 1,
             'loop_count': 2}
     action = loop.LoopAction(data)
     action.WillRunAction(None, self._tab)
     self.assertFalse(self._tab.EvaluateJavaScript(VIDEO_1_LOOP_CHECK))
     self.assertRaises(util.TimeoutException, action.RunAction, None, self._tab,
                       None)
 
   def testLoopWithoutLoopCount(self):
     """Tests that loop action fails with no loop count."""
     data = {}
     action = loop.LoopAction(data)
     action.WillRunAction(None, self._tab)
     self.assertRaises(AssertionError, action.RunAction, None, self._tab, None)