Add text size override to Viewer.

In some cases issues only happen when the actual requested text size on
a paint is a particular size. Allow overriding the text size on the
paint for such testing.

Change-Id: Ic719ea36ba9d624725d443cbd563283628606f2d
Reviewed-on: https://skia-review.googlesource.com/133446
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Ben Wagner <bungeman@google.com>
2 files changed