[Systrace] Fix systrace clock syncing issue with BattOr.

systrace/systrace/tracing_agents/atrace_agent.py

Index: systrace/systrace/tracing_agents/atrace_agent.py
diff --git a/systrace/systrace/tracing_agents/atrace_agent.py b/systrace/systrace/tracing_agents/atrace_agent.py
index 2ea1532df59a5fe69c717f476a0ab4c485c119f0..10e5b185a38532761431922d8b278c9889b95aec 100644
--- a/systrace/systrace/tracing_agents/atrace_agent.py
+++ b/systrace/systrace/tracing_agents/atrace_agent.py
@@ -15,6 +15,7 @@ from py_trace_event import trace_time as trace_time_module
 from systrace import trace_result
 from systrace import tracing_agents
 from systrace import util
+from telemetry.timeline import trace_data as trace_data_module
 
 
 # Text that ADB sends, but does not need to be displayed to the user.
@@ -204,6 +205,13 @@ class AtraceAgent(tracing_agents.TracingAgent):
     self._collection_thread = None
     return trace_result.TraceResult('systemTraceEvents', self._trace_data)
 
+  @py_utils.Timeout(tracing_agents.GET_RESULTS_TIMEOUT)
+  def CollectAgentTraceData(self, trace_data_builder):
+    self._collection_thread.join()
+    self._collection_thread = None
+    trace_data_builder.AddTraceFor(trace_data_module.ATRACE_PART,
+                                   self._trace_data)
+
   def SupportsExplicitClockSync(self):
     return True