[Telemetry][Tracing] Split StopTracing and CollectTraceData for Chrome Tracing Agent.

telemetry/telemetry/internal/platform/tracing_agent/chrome_tracing_agent_unittest.py

Index: telemetry/telemetry/internal/platform/tracing_agent/chrome_tracing_agent_unittest.py
diff --git a/telemetry/telemetry/internal/platform/tracing_agent/chrome_tracing_agent_unittest.py b/telemetry/telemetry/internal/platform/tracing_agent/chrome_tracing_agent_unittest.py
index 388c121601353c7d08ced1de6ddc4f1489643376..fb531ca514714f98b8f5a4b151ba66eac7482ced 100644
--- a/telemetry/telemetry/internal/platform/tracing_agent/chrome_tracing_agent_unittest.py
+++ b/telemetry/telemetry/internal/platform/tracing_agent/chrome_tracing_agent_unittest.py
@@ -58,6 +58,7 @@ class FakeDevtoolsClient(object):
     self.is_tracing_running = False
     self.remote_port = remote_port
     self.will_raise_exception_in_stop_tracing = False
+    self.collected = False
 
   def IsAlive(self):
     return self.is_alive
@@ -66,12 +67,16 @@ class FakeDevtoolsClient(object):
     del trace_options, timeout  # unused
     self.is_tracing_running = True
 
-  def StopChromeTracing(self, trace_data_builder):
-    del trace_data_builder  # unused
+  def StopChromeTracing(self):
     self.is_tracing_running = False
     if self.will_raise_exception_in_stop_tracing:
       raise Exception
 
+  def CollectChromeTracingData(self, trace_data_builder, timeout=30):
+    del trace_data_builder  # unused
+    del timeout # unused
+    self.collected = True
+
   def IsChromeTracingSupported(self):
     return True
 
@@ -190,19 +195,25 @@ class ChromeTracingAgentTest(unittest.TestCase):
     # port as devtool 2
     self.assertFalse(devtool4.is_tracing_running)
 
+
+    self.assertFalse(devtool1.collected)
     self.StopTracing(tracing_agent1)
+    self.assertTrue(devtool1.collected)
     self.assertFalse(devtool1.is_tracing_running)
     self.assertFalse(devtool2.is_tracing_running)
     self.assertFalse(devtool3.is_tracing_running)
     self.assertFalse(devtool4.is_tracing_running)
+
     # Test that it should be ok to start & stop tracing on platform1 again.
     tracing_agent1 = self.StartTracing(self.platform1)
     self.StopTracing(tracing_agent1)
 
     tracing_agent2 = self.StartTracing(self.platform2)
     self.assertTrue(devtool4.is_tracing_running)
+    self.assertFalse(devtool4.collected)
     self.StopTracing(tracing_agent2)
     self.assertFalse(devtool4.is_tracing_running)
+    self.assertTrue(devtool4.collected)
 
   def testFlushTracing(self):
     devtool1 = FakeDevtoolsClient(1)