Add video metrics integration test

tools/chrome_proxy/webdriver/video.py

Index: tools/chrome_proxy/webdriver/video.py
diff --git a/tools/chrome_proxy/webdriver/video.py b/tools/chrome_proxy/webdriver/video.py
index 9755e045fe301cdb0a298feb976dca399dfbb03f..eb32d6004b1b5f4b5a832c8d38a2d06ac3ae6e0d 100644
--- a/tools/chrome_proxy/webdriver/video.py
+++ b/tools/chrome_proxy/webdriver/video.py
@@ -42,6 +42,36 @@ class Video(IntegrationTest):
           self.assertHasChromeProxyViaHeader(response)
       self.assertTrue(saw_video_response, 'No video request seen in test!')
 
+  # Check the compressed video has the same frame count, width, height, and
+  # duration as uncompressed.
+  def testVideoMetrics(self):
+    expected = {
+      'duration': 60.127,
+      'webkitDecodedFrameCount': 1080.0,
+      'videoWidth': 640.0,
+      'videoHeight': 360.0
+    }
+    with TestDriver() as t:
+      t.AddChromeArg('--enable-spdy-proxy-auth')
+      t.LoadURL('http://check.googlezip.net/cacheable/video/buck_bunny_640x360_24fps_video.html')
+      # Check request vwas proxied and we got a compressed video back.
+      for response in t.GetHTTPResponses():
+        self.assertHasChromeProxyViaHeader(response)
+        if ('content-type' in response.response_headers
+            and 'video' in response.response_headers['content-type']):
+          self.assertEqual('video/webm',
+            response.response_headers['content-type'])
+      t.ExecuteJavascriptStatement('document.getElementById("video").play()')
+      # Wait for the video to finish playing, plus some headroom.
+      time.sleep(80)

[RyanSturm, 2017/02/17 19:24:10]

What is the impact of having a test that takes 80 seconds to run (impact on the
continuous test harness)? I know if you add this test, I will end up never
running all the integration tests because this one takes too long to run. I have
no suggestions on how to fix it if the test truly needs to watch the whole
video.

[Robert Ogden, 2017/02/17 19:28:18]

The test harness itself it happy to wait, but yes it'll make the whole test
suite a rather long event. This test has to play all the way through because I
don't have another way to ensure chrome decodes all the frames. Besides, so far
all the tests in this class save the XHR one wait through the entire video :/

[Tom Bergan, 2017/02/17 20:10:56]

We should be able to use a shorter video. No reason the video needs to be 60s.

+bolian
+harringtond

[bolian, 2017/02/17 20:21:57]

I am not sure how the test works internally. At least Chrome seems to know all
the duration, width, height, etc as long as the video starts playing. So, do you
need to wait for it to finish playing?

If that is not possible, adding a much shorter video sounds good to me.

+      # Check each metric against its expected value.
+      for metric in expected:
+        actual = float(t.ExecuteJavascriptStatement(
+          'document.getElementById("video").%s' % metric))
+        self.assertAlmostEqual(expected[metric], actual, msg="Compressed video "
+          "metric doesn't match expected! Metric=%s Expected=%f Actual=%f"
+          % (metric, expected[metric], actual), places=None, delta=0.25)
+
   # Check the frames of a compressed video.
   def testVideoFrames(self):
     self.instrumentedVideoTest('http://check.googlezip.net/cacheable/video/buck_bunny_640x360_24fps_video.html')