When a method such as "void m(int i, int j)" is completed, instead of
simply inserting "m()", we insert "m(i, j)", we highlight "i", and we
set up linked position groups for "i" and "j" so that the user can
press tab to move from one parameter to the next.
Optional parameters (both named and positional) are not handled by
this logic--the user must still enter them manually.
R=danrubel@google.com
Review URL: https://codereview.chromium.org//837793003
git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@42667 260f80e4-7a28-3924-810f-c04153c831b5
paulberry@google.com
94993d5cc1