Compute exact bounds for SVGPathElement::getBBox()

The current implementation relies on SkPath::getBounds(), which
computes a conservative result (includes control points).

Use SkPathOps::TightBounds() instead, for an exact answer.

BUG=230599
R=fs@opera.com,pdr@chromium.org,schenney@chromium.org,caryclark@google.com

Review-Url: https://codereview.chromium.org/2168133002
Cr-Commit-Position: refs/heads/master@{#407268}
5 files changed