[SVGDom] Add more presentation attributes.

Implement proper presentation attribute inheritance, and add
support for

* fill-opacity
* stroke-linecap
* stroke-linejoin
* stroke-opacity
* stroke-width

R=robertphillips@google.com,stephana@google.com
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2234153002

Review-Url: https://codereview.chromium.org/2234153002
11 files changed