Add checks to make sure we don't overflow 32 bit int in GPU path renderers.

Bug: chromium:848716
Change-Id: I5b8fe036c666a1f379c4125115b2cec0295711b3
Reviewed-on: https://skia-review.googlesource.com/132268
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Greg Daniel <egdaniel@google.com>
4 files changed