Remove the weak dictionary that maps tab objects to it markers

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.
 import sys
 
 from measurements import smooth_gesture_util
 from telemetry.core.timeline.model import TimelineModel
 from telemetry.page import page_measurement
 from telemetry.page.actions import action_runner
 from telemetry.web_perf import timeline_interaction_record as tir_module
@@ skipping 33 matching lines @@
       tab.browser.platform.StopRawDisplayFrameRateMeasurement()
     self._tracing_timeline_data = tab.browser.StopTracing()
     self._timeline_model = TimelineModel(
       timeline_data=self._tracing_timeline_data)
 
   def AddResults(self, tab, results):
     # Add results of smoothness metric. This computes the smoothness metric for
     # the time ranges of gestures, if there is at least one, else the the time
     # ranges from the first action to the last action.
 
-    renderer_thread = self._timeline_model.GetRendererThreadFromTab(tab)
+    renderer_thread = self._timeline_model.GetRendererThreadFromTabId(
+        tab.id)
     run_smooth_actions_record = None
     smooth_records = []
     for event in renderer_thread.async_slices:
       if not tir_module.IsTimelineInteractionRecord(event.name):
         continue
       r = tir_module.TimelineInteractionRecord.FromAsyncEvent(event)
       if r.logical_name == RUN_SMOOTH_ACTIONS:
         assert run_smooth_actions_record is None, (
           'SmoothnessController cannot issue more than 1 %s record' %
           RUN_SMOOTH_ACTIONS)
@@ skipping 27 matching lines @@
       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):
     if tab.browser.platform.IsRawDisplayFrameRateSupported():
       tab.browser.platform.StopRawDisplayFrameRateMeasurement()
     if tab.browser.is_tracing_running:
       tab.browser.StopTracing()