Revert 273986 "Remove failing expectations for pixel tests."

Re-enable the failing expectations for the Pixel.CSS3DBlueBox test.
The <meta viewport> tag added to this test is causing failures on some
desktop bots. See Issue 368495.

> Remove failing expectations for pixel tests.
> 
> This is a follow-up patch for r273755.
> 
> BUG=368495
> TBR=kbr@chromium.org
> 
> Review URL: https://codereview.chromium.org/304183008

TBR=alokp@chromium.org

Review URL: https://codereview.chromium.org/306303002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@274176 0039d316-1c4b-4281-b951-d872f2087c98

content/test/gpu/gpu_tests/pixel_expectations.py

@@ -24,4 +24,6 @@ class PixelExpectations(test_expectations.TestExpectations):
     # self.Fail('Pixel.Canvas2DRedBox',
     #     ['mac', 'amd', ('nvidia', 0x1234)], bug=123)
 
+    self.Fail('Pixel.CSS3DBlueBox', bug=368495)
+
     pass