Mark various tests as needing updated baselines after r270513.

That change changed how we convert video from yuv to rgb; the new method
is significantly faster but slightly less accurate, so we have some
low-order bit diffs in the pixel results for some tests.

TBR=mtomasz@chromium.org
BUG=347422

Review URL: https://codereview.chromium.org/288093002

git-svn-id: svn://svn.chromium.org/blink/trunk@174063 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Change EME content browser tests to use W3C test harness

There are a couple of EME tests that aren't using the W3C test harness.
In preparation for converting them to use promises, update the tests
to use the W3C test harness.

TEST=modified tests pass

Review URL: https://codereview.chromium.org/274243003

git-svn-id: svn://svn.chromium.org/blink/trunk@174064 bbb929c8-8fbe-4397-9dbb-9b2b20218538