Introduce TracingController and TracingControllerBackend skeleton

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.core.platform import tracing_category_filter
 from telemetry.timeline.model import TimelineModel
 from telemetry.page.actions import action_runner
 from telemetry.web_perf import timeline_interaction_record as tir_module
 
 
 RUN_SMOOTH_ACTIONS = 'RunSmoothAllActions'
 
 
 class TimelineController(object):
   def __init__(self):
     super(TimelineController, self).__init__()
-    self.trace_categories = tracing_backend.DEFAULT_TRACE_CATEGORIES
+    self.trace_categories = None
     self._model = None
     self._renderer_process = None
     self._smooth_records = []
     self._interaction = None
 
   def SetUp(self, page, tab):
     """Starts gathering timeline data.
 
     """
     # Resets these member variables incase this object is reused.
     self._model = None
     self._renderer_process = None
     if not tab.browser.supports_tracing:
       raise Exception('Not supported')
-    if self.trace_categories:
-      categories = [self.trace_categories] + \
-          page.GetSyntheticDelayCategories()
-    else:
-      categories = page.GetSyntheticDelayCategories()
-    tab.browser.StartTracing(','.join(categories))
+    category_filter = tracing_category_filter.TracingCategoryFilter(
+        filter_string=self.trace_categories)
+    for delay in page.GetSyntheticDelayCategories():
+      category_filter.AddSyntheticDelay(delay)
+    tab.browser.StartTracing(category_filter)
 
   def Start(self, tab):
     # Start the smooth marker for all actions.
     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()
@@ skipping 35 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