Dispatch chrome.app.runtime.onRestarted to ephemeral apps

If Chrome is restarted while an ephemeral app is running, the app will be dispatched the onRestarted() event on restart. If the app does not listen to this event, it is just relaunched.

BUG=339001
TEST=To test dispatch of the onRestarted event:
Find the "Restarted Event Sample" app in the Web Store and run it
ephemerally. Restart Chrome, e.g. using chrome://restart, and
verify that the app is restarted.

Review URL: https://codereview.chromium.org/133073014

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@248145 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 248145