GitLab

This change caches the strokes (converting them to separate paths) used
for hit-testing in SVG, so they don't need to be recomputed on every
hit-test / mouse-move.

This change is motivated by a subsequent change that will increase
hit-testing precision while significantly worsening performance.  By
caching the stroke path, the aggregate result of the two changes is
expected to perform better than the current status quo.

Bug: 964614
Change-Id: I48de70a22c2f8137604f214a699bae258ff741d8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2140819Reviewed-by: Fredrik Söderquist <fs@opera.com>
Reviewed-by: Philip Rogers <pdr@chromium.org>
Commit-Queue: Ian Prest <iapres@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#758897}