Remove usage of PathUtil from CommandHandler.

To introduce the muti profile and the separate file system, we are moving from
paths to Entry. Thic CL copies some methods from PathUtil to EntryLocation, and
removes replace usage of PathUtil with EntryLocation.

BUG=302090
TEST=manually

Review URL: https://codereview.chromium.org/96433003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@239460 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 239460