Add cleanup for measurements that use tracing

tools/perf/measurements/smoothness_controller.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.
 
 from metrics import smoothness
 from metrics import timeline_interaction_record as tir_module
 from telemetry.core.timeline.model import TimelineModel
 from telemetry.page import page_measurement
 
 import telemetry.core.timeline.bounds as timeline_bounds
@@ skipping 45 matching lines @@
     smoothness_metric = smoothness.SmoothnessMetric()
     smoothness_metric.AddResults(self._timeline_model,
                                        renderer_thread,
                                        interaction_record,
                                        results)
     if tab.browser.platform.IsRawDisplayFrameRateSupported():
       for r in tab.browser.platform.GetRawDisplayFrameRateMeasurements():
         if r.value is None:
           raise MissingDisplayFrameRateError(r.name)
         results.Add(r.name, r.unit, r.value)
+
+  def CleanUp(self, tab):

[ernstm, 2014/03/25 00:00:53]

Can you please add:
if tab.browser.platform.IsRawDisplayFrameRateSupported():
  tab.browser.platform.StopRawDisplayFrameRateMeasurement()

That would probably fix crbug.com/355773 (assuming this is meant to be called
from an exception handler and such handler is already in place).

+    if tab.browser.is_tracing_running:
+      tab.browser.StopTracing()