Add measure_trace tool allows us to measure smoothness given a timeline trace

tools/telemetry/examples/measure_trace.py

+#!/usr/bin/env python
+# 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 json
+import os
+import sys
+
+sys.path.append(os.path.join(os.path.dirname(__file__), os.pardir))
+sys.path.append(os.path.join(os.path.dirname(__file__), os.pardir, os.pardir,
+                             'perf'))
+
+from telemetry.page import page as page_module
+from telemetry.timeline import model
+from telemetry.timeline import tracing_timeline_data
+from telemetry.results import page_test_results
+from telemetry.results import buildbot_output_formatter
+from telemetry.web_perf import timeline_interaction_record as tir_module
+from telemetry.web_perf.metrics import smoothness
+# pylint: disable=F0401
+from measurements import smooth_gesture_util
+
+
+def _ExtractInteractionsRecordFromThread(thread, timeline_model):
+  records = []
+  for event in thread.async_slices:
+    if not tir_module.IsTimelineInteractionRecord(event.name):
+      continue
+    assert event.start_thread
+    assert event.start_thread is event.end_thread
+    records.append(
+        smooth_gesture_util.GetAdjustedInteractionIfContainGesture(
+            timeline_model,
+            tir_module.TimelineInteractionRecord.FromAsyncEvent(event)))
+  return records
+
+
+def Main(args):
+  if len(args) is not 1:
+    print 'Invalid arguments. Usage: measure_trace.py <trace file>'
+    return 1
+  with open(args[0]) as trace_file:
+    trace_data = tracing_timeline_data.TracingTimelineData(
+        json.load(trace_file))
+
+  timeline_model = model.TimelineModel(trace_data)
+  smoothness_metric = smoothness.SmoothnessMetric()
+  formatters = [
+      buildbot_output_formatter.BuildbotOutputFormatter(sys.stdout)
+      ]
+  results = page_test_results.PageTestResults(output_formatters=formatters)
+  page = page_module.Page('http://measure-trace-dummy-page')
+
+  results.WillRunPage(page)
+  for thread in timeline_model.GetAllThreads():
+    interaction_records = _ExtractInteractionsRecordFromThread(
+        thread, timeline_model)
+    if not any(interaction_records):
+      continue
+    for record in interaction_records:
+      smoothness_metric.AddResults(

[chrishenry, 2014/08/15 17:14:56]

This is specifically for smoothness metric? Do you intend this to support more
in the future? Shouldn't this simply uses the interaction record flags?

Why not extract something from TimelineBasedMeasurement for this?

+          timeline_model, thread, [record], results)
+  results.DidRunPage(page)
+  results.PrintSummary()
+  return 0
+
+
+if __name__ == '__main__':
+  sys.exit(Main(sys.argv[1:]))