Remove moar unused SVG methods

Review URL: https://codereview.chromium.org/183743004

git-svn-id: svn://svn.chromium.org/blink/trunk@168148 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Also use transition types when constructing Events that raise exceptions.

Follow up the switch to making Events be garbage collected in
http://codereview.chromium.org/182763002 and also use a transition
type for the result if the event constructor raises exceptions.

R=haraken@chromium.org
BUG=340522

Review URL: https://codereview.chromium.org/183973007

git-svn-id: svn://svn.chromium.org/blink/trunk@168149 bbb929c8-8fbe-4397-9dbb-9b2b20218538