Enable some profile_chrome unit tests on Trybots

systrace/profile_chrome/ddms_tracing_agent_unittest.py

Index: systrace/profile_chrome/ddms_tracing_agent_unittest.py
diff --git a/systrace/profile_chrome/ddms_tracing_agent_unittest.py b/systrace/profile_chrome/ddms_tracing_agent_unittest.py
index 3f4b59c6204fffde6b5c821fecaeed1dd02ec0d2..c3878d0e427b69de29a89b66fcb1a1f78322d05d 100644
--- a/systrace/profile_chrome/ddms_tracing_agent_unittest.py
+++ b/systrace/profile_chrome/ddms_tracing_agent_unittest.py
@@ -4,9 +4,14 @@
 
 from profile_chrome import agents_unittest
 from profile_chrome import ddms_tracing_agent
+from systrace import decorators
 
 
 class DdmsAgentTest(agents_unittest.BaseAgentTest):
+  # TODO(washingtonp): The DDMS test is flaky on the Tryserver, but it
+  # consistently passes on Android M. Need to figure out why the result data
+  # does not start with '*version' and why the test is flaky.
+  @decorators.Disabled
   def testTracing(self):
     agent = ddms_tracing_agent.DdmsAgent(self.device, self.package_info)