[filemanager] Fix startup initialization: set current root dir before updating roots.

BUG=164274
TEST=See bug.

Review URL: https://chromiumcodereview.appspot.com/11574034

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@173337 0039d316-1c4b-4281-b951-d872f2087c98
1 file changed