Polymer/PointerEvents — pull request #128 by azakus (2014-01-28 23:51:20+00:00)
Title: Workaround <use> element event path

The SVG element has a horrifying "instance tree" related to ShadowDOM, but does not retarget.
The SVGElementInstance (the instanceRoot type) has parts of a Node's API, but not all (like .contains).
For native events the SVGElementInstance will bubble events up to the element, even non-bubbling events like enter
and leave, but it will not do so when dispatchEvent is called on it with a non-bubbling event.
Only Safari, IE, and Chrome implement this monstrosity, and working group seems to agree it should be removed:
http://lists.w3.org/Archives/Public/www-svg/2014Jan/0014.html

This workaround rewites event.target and relatedTarget to refer to elements and not their "instance trees".
Fixes #124