Enable some profile_chrome unit tests on Trybots

systrace/profile_chrome/atrace_tracing_agent_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.
 
 from profile_chrome import agents_unittest
 from profile_chrome import atrace_tracing_agent
+from systrace import decorators
 
 
 class AtraceAgentTest(agents_unittest.BaseAgentTest):
+  @decorators.ClientOnlyTest
   def testGetCategories(self):
     categories = \
         atrace_tracing_agent.AtraceAgent.GetCategories(self.device)
     self.assertTrue(categories)
     assert 'gfx' in ' '.join(categories)
 
+  @decorators.NeverRunTest

[Sami, 2016/09/02 13:01:13]

For each completely disabled test, could you add a comment saying what needs to
be fixed so the test can run?

[washingtonp, 2016/09/08 22:51:36]

Done.

   def testTracing(self):
     categories = 'gfx,input,view'
     ring_buffer = False
     agent = atrace_tracing_agent.AtraceAgent(self.device,
                                              ring_buffer)
 
     try:
       agent.StartAgentTracing(atrace_tracing_agent.AtraceConfig(categories))
     finally:
       agent.StopAgentTracing()
     result = agent.GetResults()
 
     self.assertFalse(agent.IsTracingOn())
     self.assertTrue('CPU#' in result.raw_data)