ui: Rename |window_| to |compositor_host_| as previously requested.

Missed this request when landing the change to add this variable.

R=enne@chromium.org, enne
BUG=270918

Review URL: https://codereview.chromium.org/175513003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@252670 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 252670
Only support unprefixed Clear Key internally in Chromium.

For prefixed EME implementation, we always convert fix the Clear Key key system
name before passing the key system parameter down.

BUG=252065
R=ddorwin@chromium.org, jamesr@chromium.org

Review URL: https://codereview.chromium.org/173223002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@252671 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 252671