Add support for [PutForwards] IDL extended attribute

Add support for [PutForwards] IDL extended attribute in the Perl
bindings generator and use it for Document.location:
http://www.whatwg.org/specs/web-apps/current-work/multipage/dom.html#document

This CL also gets rid of custom bindings code for Document.location
and uses [PutForwards] instead.

R=haraken, abarth
BUG=307045

Review URL: https://codereview.chromium.org/27207002

git-svn-id: svn://svn.chromium.org/blink/trunk@159674 bbb929c8-8fbe-4397-9dbb-9b2b20218538