Disable SpeedIndexImplTest.testVideoCompleteness on cros.

BUG=334841
TEST=manual

Review URL: https://codereview.chromium.org/138963007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@245514 0039d316-1c4b-4281-b951-d872f2087c98

tools/perf/metrics/speedindex_unittest.py

@@ -10,6 +10,7 @@ import os
 import unittest
 
 from telemetry.core.timeline import model
+from telemetry.unittest import DisabledTestOnCrOS
 from metrics import speedindex
 
 # Sample timeline data in the json format provided by devtools.
@@ -92,6 +93,7 @@ class SpeedIndexImplTest(unittest.TestCase):
     self.assertEquals(time_area_dict[400], 200000)
     self.assertEquals(time_area_dict[800], 200000)
 
+  @DisabledTestOnCrOS
   def testVideoCompleteness(self):
     frames = [
       (0.0, FakeBitmap([100, 0, 0])),