[Telemetry] Fix video_unittest so that it actually runs on bots.

tools/telemetry/telemetry/core/video_unittest.py

Index: tools/telemetry/telemetry/core/video_unittest.py
diff --git a/tools/telemetry/telemetry/core/video_unittest.py b/tools/telemetry/telemetry/core/video_unittest.py
index e940f0f49e4d4f490dda76deb8126a4227a1e5c4..b49190d106d78006322214b926d1db1ef7b06073 100644
--- a/tools/telemetry/telemetry/core/video_unittest.py
+++ b/tools/telemetry/telemetry/core/video_unittest.py
@@ -2,30 +2,19 @@
 # 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 unittest
 
-from telemetry import benchmark
+from telemetry import decorators
 from telemetry.core import bitmap
-from telemetry.core import platform
 from telemetry.core import util
 from telemetry.core import video
 
 
 class VideoTest(unittest.TestCase):
 
-  @benchmark.Disabled
+  @decorators.Enabled('linux')
   def testFramesFromMp4(self):
-    host_platform = platform.GetHostPlatform()
-
-    try:
-      host_platform.InstallApplication('avconv')
-    finally:
-      if not host_platform.CanLaunchApplication('avconv'):
-        logging.warning('Test not supported on this platform')
-        return  # pylint: disable=W0150
-
     vid = os.path.join(util.GetUnittestDataDir(), 'vid.mp4')
     expected_timestamps = [
       0,
@@ -38,13 +27,14 @@ class VideoTest(unittest.TestCase):
       1926,
       ]
 
-    video_obj = video.Video(vid)
-
-    # Calling _FramesFromMp4 should return all frames.
-    # pylint: disable=W0212
-    for i, timestamp_bitmap in enumerate(video_obj._FramesFromMp4(vid)):
-      timestamp, bmp = timestamp_bitmap
-      self.assertEquals(timestamp, expected_timestamps[i])
-      expected_bitmap = bitmap.Bitmap.FromPngFile(os.path.join(
-          util.GetUnittestDataDir(), 'frame%d.png' % i))
-      self.assertTrue(expected_bitmap.IsEqual(bmp))
+    with open(vid) as video_file:
+      video_obj = video.Video(video_file)
+
+      # Calling _FramesFromMp4 should return all frames.
+      # pylint: disable=W0212
+      for i, timestamp_bitmap in enumerate(video_obj._FramesFromMp4()):
+        timestamp, bmp = timestamp_bitmap
+        self.assertEquals(timestamp, expected_timestamps[i])
+        expected_bitmap = bitmap.Bitmap.FromPngFile(os.path.join(
+            util.GetUnittestDataDir(), 'frame%d.png' % i))
+        self.assertTrue(expected_bitmap.IsEqual(bmp))