Add data reduction proxy integration tests for video compression.

tools/chrome_proxy/integration_tests/chrome_proxy_metrics.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.
 
 import logging
+import os
 import time
 
 from integration_tests import network_metrics
 from telemetry.page import page_test
 from telemetry.value import scalar
 
 
 class ChromeProxyMetricException(page_test.MeasurementFailure):
   pass
 
 
 CHROME_PROXY_VIA_HEADER = 'Chrome-Compression-Proxy'
 
 
 class ChromeProxyResponse(network_metrics.HTTPResponse):
-  """ Represents an HTTP response from a timeleine event."""
+  """ Represents an HTTP response from a timeline event."""
   def __init__(self, event):
     super(ChromeProxyResponse, self).__init__(event)
 
   def ShouldHaveChromeProxyViaHeader(self):
     resp = self.response
     # Ignore https and data url
     if resp.url.startswith('https') or resp.url.startswith('data:'):
       return False
     # Ignore 304 Not Modified and cache hit.
     if resp.status == 304 or resp.served_from_cache:
@@ skipping 42 matching lines @@
   def HasChromeProxyLoFi(self):
     if 'Chrome-Proxy' not in self.response.request_headers:
       return False
     chrome_proxy_request_header = self.response.request_headers['Chrome-Proxy']
     values = [v.strip() for v in chrome_proxy_request_header.split(',')]
     for value in values:
       if len(value) == 5 and value == 'q=low':
         return True
     return False
 
+
 class ChromeProxyMetric(network_metrics.NetworkMetric):
   """A Chrome proxy timeline metric."""
 
   def __init__(self):
     super(ChromeProxyMetric, self).__init__()
     self.compute_data_saving = True
 
   def SetEvents(self, events):
     """Used for unittest."""
     self._events = events
@@ skipping 458 matching lines @@
         via_count += 1
     if via_count == 0:
       raise ChromeProxyMetricException, (
           'Expected at least one response through the proxy after the bypass '
           'expired, but zero such responses were received.')
 
     results.AddValue(scalar.ScalarValue(
         results.current_page, 'bypass', 'count', bypass_count))
     results.AddValue(scalar.ScalarValue(
         results.current_page, 'via', 'count', via_count))
+
+
+PROXIED = 'proxied'
+DIRECT = 'direct'
+
+class ChromeProxyVideoMetric(network_metrics.NetworkMetric):
+  """Wraps the video metrics produced by videowrapper.js. Also checks a few

[sclittle, 2015/04/11 00:13:02]

See style guide:
https://google-styleguide.googlecode.com/svn/trunk/pyguide.html?showone=Comme...

[Tom Bergan, 2015/05/01 23:48:28]

Done.

+     basic HTTP response headers such as Content-Type and Content-Length for
+     the video responses.
+  """
+
+  def __init__(self, tab):
+    super(ChromeProxyVideoMetric, self).__init__()
+    with open(os.path.join(os.path.dirname(__file__), 'videowrapper.js')) as f:
+      js = f.read()
+      tab.ExecuteJavaScript(js)
+
+  def Start(self, page, tab):
+    tab.ExecuteJavaScript('window.__chromeProxyCreateVideoWrappers()')
+    self.videoMetrics = None
+    super(ChromeProxyVideoMetric, self).Start(page, tab)
+
+  def Stop(self, page, tab):
+    tab.WaitForJavaScriptExpression('window.__chromeProxyVideoLoaded', 30)
+    m = tab.EvaluateJavaScript('window.__chromeProxyVideoMetrics')
+
+    # Now wait for the video to stop playing.
+    # Give it 2x the total duration to account for buffering.
+    waitTime = 2 * m['video_duration']
+    tab.WaitForJavaScriptExpression('window.__chromeProxyVideoEnded', waitTime)
+
+    # Load the final metrics.
+    m = tab.EvaluateJavaScript('window.__chromeProxyVideoMetrics')
+    self.videoMetrics = m
+    # Cast this to an integer as it is often approximate (for an unknown reason)
+    m['video_duration'] = int(m['video_duration'])
+    super(ChromeProxyVideoMetric, self).Stop(page, tab)
+
+  def ResponseFromEvent(self, event):
+    return ChromeProxyResponse(event)
+
+  def AddResults(self, tab, results):
+    raise NotImplementedError
+
+  def AddResultsForProxied(self, tab, results):
+    return self._AddResultsShared(PROXIED, tab, results)
+
+  def AddResultsForDirect(self, tab, results):
+    return self._AddResultsShared(DIRECT, tab, results)
+
+  def _AddResultsShared(self, kind, tab, results):
+    def err(s):
+      raise ChromeProxyMetricException, s
+
+    # Should have played the video.
+    if not self.videoMetrics['ready']:
+      err('%s: video not played' % kind)
+
+    # Should have an HTTP response for the video.
+    wantContentType = 'video/webm' if kind == PROXIED else 'video/mp4'
+    found = False
+    for r in self.IterResponses(tab):
+      resp = r.response
+      if kind == DIRECT and r.HasChromeProxyViaHeader():
+        err('%s: page has proxied Via header' % kind)
+      if resp.GetHeader('Content-Type') != wantContentType:
+        continue
+      if found:
+        err('%s: multiple video responses' % kind)
+      found = True
+
+      cl = resp.GetHeader('Content-Length')
+      xocl = resp.GetHeader('X-Original-Content-Length')
+      if cl != None:
+        self.videoMetrics['content_length_header'] = int(cl)
+      if xocl != None:
+        self.videoMetrics['x_original_content_length_header'] = int(xocl)
+
+      # Should have CL always.
+      if cl == None:
+        err('%s: missing ContentLength' % kind)
+      # Proxied: should have CL < XOCL
+      # Direct: should not have XOCL
+      if kind == PROXIED:
+        if xocl == None or int(cl) >= int(xocl):
+          err('%s: bigger response (%s > %s)' % (kind, str(cl), str(xocl)))
+      else:
+        if xocl != None:
+          err('%s: has XOriginalContentLength' % kind)
+
+    if not found:
+      err('%s: missing video response' % kind)
+
+    # Finally, add all the metrics to the results.
+    for (k,v) in self.videoMetrics.iteritems():

[sclittle, 2015/04/11 00:13:02]

Could you just call results.AddValue(...) inline above instead of building up a
dict of results?

[Tom Bergan, 2015/05/01 23:48:28]

This dict is used by ChromeProxyVideoValidation (in
chrome_proxy_measurements.py) when comparing proxied and direct fetches. I could
just call results.AddValue instead of making this dict, but then it becomes
harder to do the comparison in ChromeProxyVideoValidation because it's more
cumbersome to extract values from results.

+      k = "%s_%s" % (k, kind)
+      results.AddValue(scalar.ScalarValue(results.current_page, k, "", v))