Add GetThreadToInteractionRecordsMapsFromModel method to timeline_interaction_record.

tools/perf/measurements/timeline_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 measurements import smooth_gesture_util
 
 from telemetry.core.backends.chrome import tracing_backend
 from telemetry.timeline.model import TimelineModel
 from telemetry.page.actions import action_runner
 from telemetry.web_perf import timeline_interaction_record as tir_module
 
@@ skipping 31 matching lines @@
     runner = action_runner.ActionRunner(tab)
     self._interaction = runner.BeginInteraction(
         RUN_SMOOTH_ACTIONS, is_smooth=True)
 
   def Stop(self, tab):
     # End the smooth marker for all actions.
     self._interaction.End()
     # Stop tracing.
     timeline_data = tab.browser.StopTracing()
     self._model = TimelineModel(timeline_data)
-    self._renderer_process = self._model.GetRendererProcessFromTabId(tab.id)
-    renderer_thread = self.model.GetRendererThreadFromTabId(tab.id)
-
+    threads_to_records_map = (
+        tir_module.GetThreadToInteractionRecordsMapsFromModel(
+            self._model))
+    assert len(threads_to_records_map) == 1, (
+        'timeline metrics only support interaction records issued from'
+        'a single thread.')
+    renderer_thread = threads_to_records_map.keys()[0]
+    interaction_records = threads_to_records_map.values()[0]
+    self._renderer_process = renderer_thread.parent
     run_smooth_actions_record = None
     self._smooth_records = []
-    for event in renderer_thread.async_slices:
-      if not tir_module.IsTimelineInteractionRecord(event.name):
-        continue
-      r = tir_module.TimelineInteractionRecord.FromAsyncEvent(event)
+    for r in interaction_records:
       if r.label == RUN_SMOOTH_ACTIONS:
         assert run_smooth_actions_record is None, (
           'TimelineController cannot issue more than 1 %s record' %
           RUN_SMOOTH_ACTIONS)
         run_smooth_actions_record = r
       elif r.is_smooth:
         self._smooth_records.append(
           smooth_gesture_util.GetAdjustedInteractionIfContainGesture(
             self.model, r))
 
@@ skipping 13 matching lines @@
   def model(self):
     return self._model
 
   @property
   def renderer_process(self):
     return self._renderer_process
 
   @property
   def smooth_records(self):
     return self._smooth_records