Pass a Feature* to IsAnyFeatureAvailableToContext instead of a string name.

This makes it clear that we were never passing non-feature function names, which
lets us simplify the test.

BUG=305000

Review URL: https://codereview.chromium.org/109683007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@241490 0039d316-1c4b-4281-b951-d872f2087c98
Changes to enable HTML5 autoplay for voice search.

* Added methods in ContentViewCore to enable/disable html5 autoplay restrictions.

BUG=323264

Review URL: https://codereview.chromium.org/86443002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@241491 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 241490
SVN changes up to revision 241491