Capture only a 300x300 area with video pixel tests.

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 116 matching lines @@
 
     PixelTestPage(
       'pixel_background.html',
       base_name + '_SolidColorBackground',
       test_rect=[500, 500, 100, 100],
       revision=1),
 
     PixelTestPage(
       'pixel_video_mp4.html',
       base_name + '_Video_MP4',
-      test_rect=[0, 0, 400, 300],
-      revision=1),
+      test_rect=[0, 0, 300, 300],
+      revision=2),
 
     PixelTestPage(
       'pixel_video_vp9.html',
       base_name + '_Video_VP9',
-      test_rect=[0, 0, 400, 300],
-      revision=1),
+      test_rect=[0, 0, 300, 300],
+      revision=2),
   ]
 
 
 # Pages that should be run with GPU rasterization enabled.
 def GpuRasterizationPages(base_name):
   browser_args = ['--force-gpu-rasterization']
   return [
     PixelTestPage(
       'pixel_background.html',
       base_name + '_GpuRasterization_BlueBox',
@@ skipping 325 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']),
   ]