Web Inspector: ability to use AnchorBox as an anchor for Popover
https://bugs.webkit.org/show_bug.cgi?id=113563

Patch by Andrey Lushnikov <lushnikov@chromium.org> on 2013-03-29
Reviewed by Pavel Feldman.

No new test: no change in behaviour.

- Ability to pass AnchorBox instead of Element for popover anchor.

* inspector/front-end/Popover.js:
(WebInspector.Popover.prototype._positionElement):
(WebInspector.PopoverHelper.prototype._eventInHoverElement):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@147209 268f45cc-cd09-0410-ab3c-d52691b4dbfc