Files.app: Replace 'activate' evnets with 'click' evnets.

Currently some menu items handle the 'activate' events that are deprecated.  In
addition, handling 'activate' events prevents the file list from getting the
focus after clicking the menu items changing the list type.

This CL replace the event type.

BUG=248479
TEST=manually

Review URL: https://codereview.chromium.org/24314002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@225973 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 225973