Add video pixel tests for DirectComposition layers.

content/test/gpu/gpu_tests/pixel_test_pages.py

 # Copyright 2016 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.
 
 class PixelTestPage(object):
   """A wrapper class mimicking the functionality of the PixelTestsStorySet
   from the old-style GPU tests.
   """
   def __init__(self, url, name, test_rect, revision,
                tolerance=2, browser_args=None, expected_colors=None):
@@ skipping 469 matching lines @@
       test_rect=[0, 0, 300, 300],
       revision=4),
     PixelTestPage(
       'filter_effects.html',
       base_name + '_CSSFilterEffects_NoOverlays',
       test_rect=[0, 0, 300, 300],
       revision=4,
       tolerance=10,
       browser_args=['--disable-mac-overlays']),
   ]
+
+def DirectCompositionPages(base_name):
+  browser_args = ['--enable-direct-composition-layers']
+  return [
+    PixelTestPage(
+      'pixel_video_mp4.html',
+      base_name + '_DirectComposition_Video_MP4',
+      test_rect=[0, 0, 300, 300],
+      revision=1,
+      browser_args=browser_args),
+
+    PixelTestPage(
+      'pixel_video_vp9.html',
+      base_name + '_DirectComposition_Video_VP9',
+      test_rect=[0, 0, 300, 300],
+      revision=1,
+      browser_args=browser_args),
+  ]