Refactor TraceData to encapsulate internal traces' representation

telemetry/telemetry/web_perf/timeline_based_measurement.py

Index: telemetry/telemetry/web_perf/timeline_based_measurement.py
diff --git a/telemetry/telemetry/web_perf/timeline_based_measurement.py b/telemetry/telemetry/web_perf/timeline_based_measurement.py
index c86e98464873b1bdf7b65ae1b4fd97043c8349b2..5b5cc0ba29abab3dae143f931d6ddca48b8214f6 100644
--- a/telemetry/telemetry/web_perf/timeline_based_measurement.py
+++ b/telemetry/telemetry/web_perf/timeline_based_measurement.py
@@ -10,7 +10,6 @@ from tracing.metrics import metric_runner
 from telemetry.timeline import chrome_trace_category_filter
 from telemetry.timeline import model as model_module
 from telemetry.timeline import tracing_config
-from telemetry.timeline import trace_data as trace_data_module
 from telemetry.value import trace
 from telemetry.value import common_value_helpers
 from telemetry.web_perf.metrics import timeline_based_metric
@@ -292,29 +291,24 @@ class TimelineBasedMeasurement(story_test.StoryTest):
     trace_value = trace.TraceValue(results.current_page, trace_result)
     results.AddValue(trace_value)
 
-    if self._tbm_options.GetTimelineBasedMetrics():
-      self._ComputeTimelineBasedMetrics(results, trace_value)
-      # Legacy metrics can be computed, but only if explicitly specified.
-      if self._tbm_options.GetLegacyTimelineBasedMetrics():
-        # Since this imports the trace model in python, it will also clean up
-        # the trace handles for us.
-        self._ComputeLegacyTimelineBasedMetrics(results, trace_result)
+    try:
+      if self._tbm_options.GetTimelineBasedMetrics():
+        self._ComputeTimelineBasedMetrics(results, trace_value)
+        # Legacy metrics can be computed, but only if explicitly specified.
+        if self._tbm_options.GetLegacyTimelineBasedMetrics():
+          self._ComputeLegacyTimelineBasedMetrics(results, trace_result)
       else:
-        # Clean up the trace handles ourselves if we did not use the python
-        # trace importer.
-        for data in trace_result.GetTracesFor(
-            trace_data_module.CHROME_TRACE_PART):
-          if isinstance(data, trace_data_module.TraceFileHandle):
-            data.Clean()
-    else:
-      # Run all TBMv1 metrics if no other metric is specified (legacy behavior)
-      if not self._tbm_options.GetLegacyTimelineBasedMetrics():
-        logging.warn('Please specify the TBMv1 metrics you are interested in '
-                     'explicitly. This implicit functionality will be removed '
-                     'on July 17, 2016.')
-        self._tbm_options.SetLegacyTimelineBasedMetrics(
-            _GetAllLegacyTimelineBasedMetrics())
-      self._ComputeLegacyTimelineBasedMetrics(results, trace_result)
+        # Run all TBMv1 metrics if no other metric is specified
+        # (legacy behavior)
+        if not self._tbm_options.GetLegacyTimelineBasedMetrics():
+          logging.warn('Please specify the TBMv1 metrics you are interested in '
+                       'explicitly. This implicit functionality will be removed'
+                       ' on July 17, 2016.')
+          self._tbm_options.SetLegacyTimelineBasedMetrics(
+              _GetAllLegacyTimelineBasedMetrics())
+        self._ComputeLegacyTimelineBasedMetrics(results, trace_result)
+    finally:
+      trace_result.CleanUpAllTraces()
 
   def DidRunStory(self, platform):
     """Clean up after running the story."""