Add oem mount point to cros_mount_provider.

The new mount point will be accessible will be accessible by file manager
extension, but it won't be shown in the UI.
The mount point will contain Timescapes-ChromeOS video which will be playable in
the media player.

BUG=152216
TEST=manual (tried playing video on oem mount point using media player)


Review URL: https://chromiumcodereview.appspot.com/10993066

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@159856 0039d316-1c4b-4281-b951-d872f2087c98
10 files changed