Use constexpr version of min/max

Build-Debian9-Clang-arm-Debug-Chromebook_GLES is using c++11
version of the c++ standard libaray where min is not constexpr.

Change-Id: I631b80d373109ca845129f8f9cfd64ee0b9feff5
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/244299
Reviewed-by: Ben Wagner <bungeman@google.com>
Commit-Queue: Ben Wagner <bungeman@google.com>
Commit-Queue: Herb Derby <herb@google.com>
Auto-Submit: Herb Derby <herb@google.com>
1 file changed