copy points in array that may stretch

Description:
Potential SkOpSegment::addT() use-after-free

The 'pt' arg can be a reference to a point stored in the local fTs
TDArray => appending may cause a realloc and leave the reference
pointing to deallocated mem.

Copy the points from the stretchy array before adding them.

R=fmalita@google.com, fmalita@chromium.org, fmalita
BUG=405417

Author: caryclark@google.com

Review URL: https://codereview.chromium.org/489853002
1 file changed