Revert "Clean up proprietary codec checks/expectations in LayoutTests"

This reverts commit 117b9d3a698a52d96857b31caeb72c2e74f2a782.

Reason for revert: CL is fine, but it depends on another CL that was reverted: https://chromium-review.googlesource.com/c/chromium/src/+/836414

That CL will probably land again, so expecting to reland this one as is % rebase.

Original change's description:
> Clean up proprietary codec checks/expectations in LayoutTests
> 
> This is mostly a reland of
> https://chromium-review.googlesource.com/c/chromium/src/+/807604
> with some improvements and now unblocked by changes to bots.
> 
> Media layout tests need repair
> 1) Many tests check for proprietary codec support by only asking about
>    "video/mp4" without specifying a codec. This check is busted
>    because MP4 is no longer considered proprietary while codecs like
>    H264 and AAC still are. We currently claim "video/mp4" is entirely
>    unsupported via test hacks to avoid breaking those checks.
> 2) Some MSE tests focus on MP4 with H264. While many bots now have the
>    needed codecs, we artificially remove their support via test-only
>    hacks in order to keep expectations the same for all runners.
> 
> This CL does the following
> 1) Remove incomplete checks for "video/mp4" - instead hardcode use of
>    the .ogv files (preserving the existing behavior).
> 2) Update MSE mp4/h264 test expectations to PASS. Starting this week
>    all webkit bots include the needed codecs.
> 3) Remove test hacks that artificially reduce codec support.
> 
> It is also not a goal to make LayoutTests try all the supported codecs.
> That is covered by unit/integration tests.
> 
> Due to 3) above, some external/wpt/media-source tests now fail because
> they select mp4. Fixing these failures is tracked in Issue 794338.
> 
> TBR: dalecurtis@chromium.org, peter@chromium.org
> Bug: 327115,746579,787575,568704,794338
> Change-Id: I8443d32fc9871c887d0009605cf8876521844916
> Reviewed-on: https://chromium-review.googlesource.com/827649
> Reviewed-by: Chrome Cunningham <chcunningham@chromium.org>
> Commit-Queue: Chrome Cunningham <chcunningham@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#525212}

TBR=dalecurtis@chromium.org,peter@chromium.org,chcunningham@chromium.org

Change-Id: I4dbb4a6ad23a18e2eab5af62a2d669a477e8eaf2
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 327115, 746579, 787575, 568704, 794338
Reviewed-on: https://chromium-review.googlesource.com/837247
Reviewed-by: Chrome Cunningham <chcunningham@chromium.org>
Commit-Queue: Chrome Cunningham <chcunningham@chromium.org>
Cr-Commit-Position: refs/heads/master@{#525391}
503 files changed