clovis: Identify prefetchable resources from dependencies and tracing.

tools/android/loading/test_utils.py

 # Copyright 2016 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.
 
 """Common utilities used in unit tests, within this directory."""
 
 import devtools_monitor
 import loading_model
 import loading_trace
 import page_track
@@ skipping 107 matching lines @@
       'loadingFinished': end_time - start_time,
       'requestTime': start_time / 1000.0}
   return MakeRequestWithTiming(
       url, source_url, timing_dict, magic_content_type, initiator_type)
 
 
 def LoadingTraceFromEvents(requests, page_events=None, trace_events=None):
   """Returns a LoadingTrace instance from a list of requests and page events."""
   request = FakeRequestTrack(requests)
   page_event_track = FakePageTrack(page_events if page_events else [])
-  if trace_events:
+  if trace_events is not None:
     tracing_track = tracing.TracingTrack(None)
     tracing_track.Handle('Tracing.dataCollected',
                          {'params': {'value': [e for e in trace_events]}})
   else:
     tracing_track = None
   return loading_trace.LoadingTrace(
       None, None, page_event_track, request, tracing_track)
 
 
 class SimpleLens(object):
@@ skipping 61 matching lines @@
     """Mocked method."""
     self.no_response_requests_seen.append((method, params))
 
   def SyncRequest(self, method, params=None):
     """Mocked method."""
     expected_params, response = self._expected_responses[method].pop(0)
     if not self._expected_responses[method]:
       del self._expected_responses[method]
     self._test_case.assertEqual(expected_params, params)
     return response