Use wider types to compute bounds area and avoid overflow

Bug: skia:
Change-Id: I3ea8c8acf56d103a8f38e652b418239e0f517839
Reviewed-on: https://skia-review.googlesource.com/52720
Reviewed-by: Robert Phillips <robertphillips@google.com>
Reviewed-by: Jim Van Verth <jvanverth@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
1 file changed