Remove dependency to FileSystem from video_player and photo_import.

FileSystem is managed by VolumeManager. This CL replaces direct access to FileSystem by VolumeManager.

BUG=268233
TEST=tested manually.
R=mtomasz@chromium.org

Review URL: https://codereview.chromium.org/24538005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@225678 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 225678