Enable some profile_chrome unit tests on Trybots

systrace/profile_chrome/perf_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.
 
 import json
 
 from profile_chrome import agents_unittest
 from profile_chrome import perf_tracing_agent
 from profile_chrome import ui
+from systrace import decorators
 
 
 class PerfProfilerAgentTest(agents_unittest.BaseAgentTest):
+  @decorators.ClientOnlyTest
   def testGetCategories(self):
     if not perf_tracing_agent.PerfProfilerAgent.IsSupported():
       return
     categories = \
         perf_tracing_agent.PerfProfilerAgent.GetCategories(self.device)
     assert 'cycles' in ' '.join(categories)
 
+  # TODO(washingtonp): Try enabling this test for the SimpleperfProfilerAgent,
+  # which will be added later.
+  @decorators.Disabled
   def testTracing(self):
     if not perf_tracing_agent.PerfProfilerAgent.IsSupported():
       return
     ui.EnableTestMode()
     categories = 'cycles'
     agent = perf_tracing_agent.PerfProfilerAgent(self.device)
 
     try:
       agent.StartAgentTracing(perf_tracing_agent.PerfConfig(categories))
     finally:
       agent.StopAgentTracing()
 
     result = agent.GetResults()
     json.loads(result.raw_data)