Make recording basic media metrics optional.

tools/perf/metrics/media.py

 # Copyright 2013 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 logging
 import os
 
 from metrics import Metric
 
+
 class MediaMetric(Metric):
   """MediaMetric class injects and calls JS responsible for recording metrics.
 
   Default media metrics are collected for every media element in the page,
   such as decoded_frame_count, dropped_frame_count, decoded_video_bytes, and
   decoded_audio_bytes.
   """
+
   def __init__(self, tab):
     super(MediaMetric, self).__init__()
     with open(os.path.join(os.path.dirname(__file__), 'media.js')) as f:
       js = f.read()
       tab.ExecuteJavaScript(js)
     self._results = None
+    self._skip_basic_metrics = False
 
   def Start(self, page, tab):
     """Create the media metrics for all media elements in the document."""
+    if hasattr(page.page_set, 'skip_basic_metrics'):
+      self._skip_basic_metrics = page.page_set.skip_basic_metrics
     tab.ExecuteJavaScript('window.__createMediaMetricsForDocument()')
 
   def Stop(self, page, tab):
     self._results = tab.EvaluateJavaScript('window.__getAllMetrics()')
 
   def AddResults(self, tab, results):
     """Reports all recorded metrics as Telemetry perf results."""
     assert self._results
     for media_metric in self._results:
       self._AddResultsForMediaElement(media_metric, results)
@@ skipping 16 matching lines @@
       for m in metrics:
         if m.startswith(metric):
           special_label = m[len(metric):]
           results.Add(trace + special_label, unit, str(metrics[m]),
                       chart_name=metric, data_type='default')
 
     trace = media_metric['id']
     if not trace:
       logging.error('Metrics ID is missing in results.')
       return
-    AddOneResult('decoded_audio_bytes', 'bytes')
-    AddOneResult('decoded_video_bytes', 'bytes')
-    AddOneResult('decoded_frame_count', 'frames')
-    AddOneResult('dropped_frame_count', 'frames')
-    AddOneResult('playback_time', 'sec')
+
+    if not self._skip_basic_metrics:
+      AddOneResult('decoded_audio_bytes', 'bytes')
+      AddOneResult('decoded_video_bytes', 'bytes')
+      AddOneResult('decoded_frame_count', 'frames')
+      AddOneResult('dropped_frame_count', 'frames')
+      AddOneResult('time_to_play', 'sec')
+      AddOneResult('playback_time', 'sec')
+
     AddOneResult('seek', 'sec')
-    AddOneResult('time_to_play', 'sec')