[telemetry] Sort imports in Telemetry and its dependents.

tools/perf/metrics/webrtc_stats_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.
 
 import unittest
 
+from telemetry.unittest_util import simple_mock
+
 from metrics import webrtc_stats
-from telemetry.unittest_util import simple_mock
 
 
 SAMPLE_JSON = '''
 [[
    [
       {
          "googFrameHeightInput":"480",
          "googFrameWidthInput":"640",
          "googFrameRateSent": "23",
          "packetsLost":"-1",
@@ skipping 114 matching lines @@
                      'peer_connection_1_video_goog_max_decode_ms')
     self.assertEqual(results.received_values[3].name,
                      'peer_connection_1_video_packets_received')
     self.assertEqual(results.received_values[4].name,
                      'peer_connection_1_video_goog_decode_ms')
 
   def testReturnsIfJsonIsEmpty(self):
     results = self._RunMetricOnJson('[]')
     self.assertFalse(results.received_values)