Improve the auto-update process by also delaying updates to old-style packaged apps while the app is still in use.

BUG=301827

Review URL: https://codereview.chromium.org/45863008

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@232632 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 232632