Revert of [Ozone] Fix Vaapi unittest builds (patchset #1 id:1 of...

Revert of [Ozone] Fix Vaapi unittest builds (patchset #1 id:1 of https://codereview.chromium.org/1014623003/)

Reason for revert:
Breaks CrOS !ozone build.

Original issue's description:
> [Ozone] Fix Vaapi unittest builds
>
> BUG=none
>
> Committed: https://crrev.com/638dcf8ea48510475248361caeca547c4541b950
> Cr-Commit-Position: refs/heads/master@{#320758}

TBR=dnicoara@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=none

Review URL: https://codereview.chromium.org/1012213002

Cr-Commit-Position: refs/heads/master@{#320962}

content/content_tests.gypi

@@ -1663,7 +1663,6 @@
               '../testing/gtest.gyp:gtest',
               '../third_party/libyuv/libyuv.gyp:libyuv',
               '../ui/gfx/gfx.gyp:gfx_geometry',
-              '../ui/ozone/ozone.gyp:ozone',
             ],
             'sources': [
               'common/gpu/media/vaapi_h264_decoder_unittest.cc',