GitLab

By this CL, fileBrowserPrivate.getMountPoints starts to return Drive
(if mounted). This is the preparation for getting rid of rootList in
DocumentModel.

BUG=279276
TEST=Ran unit_tests and tested manually.

Review URL: https://chromiumcodereview.appspot.com/23541009

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@223614 0039d316-1c4b-4281-b951-d872f2087c98