Add a UseCounter for HTMLMediaElement.controller
MediaController isn't getting the attention it needs right now. Count
usage to help decide whether or not removal is feasible. Feasible does
not imply desirable, but the data can inform the decision.
Count a non-null controller without distinguishing how it was set
(markup or script) to measure the usage that affects behavior.
BUG=none
Review URL: https://codereview.chromium.org/156493002
git-svn-id: svn://svn.chromium.org/blink/trunk@166651 bbb929c8-8fbe-4397-9dbb-9b2b20218538
2 files changed
