Change SkScalarTruncToInt to saturate.

This is the same behavior as SkScalarFloorToInt, SkScalarCeilToInt, and SkScalarRoundToInt.

Bug: skia:4632
Change-Id: Iec454e841b05c5b10f335b5b089718db56740323
Reviewed-on: https://skia-review.googlesource.com/47400
Reviewed-by: Mike Reed <reed@google.com>
Reviewed-by: Mike Klein <mtklein@chromium.org>
Commit-Queue: Ben Wagner <benjaminwagner@google.com>
3 files changed