Revert of Revert "[Clock sync] Use clock sync manager to convert trace event timestamps"

telemetry/telemetry/web_perf/timeline_based_measurement.py

Index: telemetry/telemetry/web_perf/timeline_based_measurement.py
diff --git a/telemetry/telemetry/web_perf/timeline_based_measurement.py b/telemetry/telemetry/web_perf/timeline_based_measurement.py
index 9ca3a26b63412bc15259a8ae4e03e1e68858d002..54b947632a595584ee511191ea66ed185dd86fab 100644
--- a/telemetry/telemetry/web_perf/timeline_based_measurement.py
+++ b/telemetry/telemetry/web_perf/timeline_based_measurement.py
@@ -271,6 +271,13 @@ class TimelineBasedMeasurement(story_test.StoryTest):
     """Configure and start tracing."""
     if not platform.tracing_controller.IsChromeTracingSupported():
       raise Exception('Not supported')
+    if self._tbm_options.enable_chrome_trace:
+      # Alwasy enable 'blink.console' category for:
+      # 1) Backward compat of chrome clock sync (crbug.com/646925)
+      # 2) Allows users to add trace event through javascript.
+      # Notes that blink.console is extremely low-overhead, so this doesn't
+      # affect the tracing overhead budget much.
+      self._tbm_options.category_filter.AddIncludedCategory('blink.console')
     platform.tracing_controller.StartTracing(self._tbm_options.config)
 
   def Measure(self, platform, results):