tools/skui: put all enums in a common namespace

Change-Id: Icd331e8946d80652750b8b6ea0db65f5f676ac3e
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/238058
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Hal Canary <halcanary@google.com>
52 files changed