Revert "Revert "Add mskp player, use in viewer slide""

This reverts commit 0d174586c46923098eca1684e21a7049d5b62116.

Use SkTLazy instead of std::optional (C++17 library feature)

Bug: skia:11900
Change-Id: Ia41caa9322d812f9ba6644dd14ede7d0015cf8b3
Cq-Include-Trybots: luci.skia.skia.primary:Housekeeper-PerCommit-CreateDockerImage_Skia_Release,Build-Debian10-Clang-x86_64-Release-CMake
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/402642
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>
7 files changed