Don't leave fResScale uninitialized when constructing an SkStroke.

Set a default value of 1.  Users can set it with setResScale, but it's better
that the constructor doesn't just leave the field uninitialized otherwise.

R=reed@google.com
BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2207753003

Review-Url: https://codereview.chromium.org/2207753003
1 file changed