[Files.app] Fix an error on executing new task after suggest an app dialog.

BUG=323650
TEST=manually tested

Review URL: https://codereview.chromium.org/89703003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@237550 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 237550