Use Systrace tracing controller in profile_chrome

systrace/profile_chrome/profiler_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 os
 import tempfile
 import unittest
 import zipfile
 
 from profile_chrome import profiler
 from profile_chrome import ui
 from systrace import trace_result
 
 
 class FakeAgent(object):
   def __init__(self, contents='fake-contents'):
     self.contents = contents
     self.stopped = False
     self.filename = None
     self.config = None
     self.timeout = None
 
   def StartAgentTracing(self, config, timeout=None):
     self.config = config
     self.timeout = timeout
+    return True
 
   # pylint: disable=unused-argument
   def StopAgentTracing(self, timeout=None):
     self.stopped = True
+    return True
 
   # pylint: disable=unused-argument
   def GetResults(self, timeout=None):
-    trace_data = open(self.PullTrace()).read()
+    trace_data = open(self._PullTrace()).read()
     return trace_result.TraceResult('fakeData', trace_data)
 
-  def PullTrace(self):
+  def _PullTrace(self):
     with tempfile.NamedTemporaryFile(delete=False) as f:
       self.filename = f.name
       f.write(self.contents)
       return f.name
 
   # pylint: disable=no-self-use
   def SupportsExplicitClockSync(self):
     return False
 
   # pylint: disable=unused-argument, no-self-use
@@ skipping 36 matching lines @@
   def testCaptureMultipleProfiles(self):
     agents = [FakeAgent('c1'), FakeAgent('c2')]
     result = profiler.CaptureProfile(None, agents, 1, write_json=True)
 
     try:
       self.assertTrue(result.endswith('.zip'))
       self.assertTrue(zipfile.is_zipfile(result))
     finally:
       if os.path.exists(result):
         os.remove(result)