Allow hyphen and underscore in host name in adb port forwarding dialog.

BUG=336394

Review URL: https://codereview.chromium.org/133503009

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@248213 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 248213