SVGPathSegList was missing SetWrapperReference call to contextElement.
SVGPathSegList was missing SetWrapperReference call to contextElement.

This caused the contextElement to be gc-ed while its tearoffs are active, leading to use-after-free.

BUG=308818
BUG=346110

Review URL: https://codereview.chromium.org/176683002

git-svn-id: bf5cd6ccde378db821296732a091cfbcf5285fbd@167656 bbb929c8-8fbe-4397-9dbb-9b2b20218538

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