Allow webview API in an unblessed extension process

BUG=293724

Review URL: https://codereview.chromium.org/24243007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@225493 0039d316-1c4b-4281-b951-d872f2087c98
After registration, add printer to top of list without re-requesting from server

After registration, instead of refreshing the printer list from the server, add
the newly registered printer to the top of the list. This stops bugs in which
the printer list on the server is not yet up-to-date when the request is sent.

BUG=298535

Review URL: https://codereview.chromium.org/24467005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@225494 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 225493
SVN changes up to revision 225494