Introduce TracingController and TracingControllerBackend skeleton

tools/perf/measurements/thread_times.py

Index: tools/perf/measurements/thread_times.py
diff --git a/tools/perf/measurements/thread_times.py b/tools/perf/measurements/thread_times.py
index 2c3e6346ac95c7449a053e7119f27cda47f8cf79..3a7c97937c157b72a85f6be23cd4e42f6dd1b75c 100644
--- a/tools/perf/measurements/thread_times.py
+++ b/tools/perf/measurements/thread_times.py
@@ -3,7 +3,7 @@
 # found in the LICENSE file.
 from measurements import timeline_controller
 from metrics import timeline
-from telemetry.core.backends.chrome import tracing_backend
+from telemetry.core.platform import tracing_category_filter
 from telemetry.page import page_measurement
 
 class ThreadTimes(page_measurement.PageMeasurement):
@@ -22,11 +22,10 @@ class ThreadTimes(page_measurement.PageMeasurement):
     self._timeline_controller = timeline_controller.TimelineController()
     if self.options.report_silk_details:
       # We need the other traces in order to have any details to report.
-      self.timeline_controller.trace_categories = \
-          tracing_backend.DEFAULT_TRACE_CATEGORIES
+      self.timeline_controller.trace_categories = None
     else:
       self._timeline_controller.trace_categories = \
-          tracing_backend.MINIMAL_TRACE_CATEGORIES
+          tracing_category_filter.CreateNoOverheadFilter().filter_string
     self._timeline_controller.SetUp(page, tab)
 
   def WillRunActions(self, page, tab):