Combobox: Have the first item not rendered for an action combobox

This CL skips rendering the first item and separators on the dropdown
menu for an 'action' combobox.

BUG=341994
TEST=manual

Review URL: https://codereview.chromium.org/178003009

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@253531 0039d316-1c4b-4281-b951-d872f2087c98
Reload the host list if host JID appears to be invalid

On connection failure (when the host appears to be offline), the
Android Chromoting client will reload the host list and re-attempt the
connection automatically.

BUG=304719

Review URL: https://codereview.chromium.org/179063004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@253532 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 253532