Simplify color and translate updates

Close over all the fields for updating the color and translation. Remove unneeded
accessors. Simplify the calculation of the translation.

Change-Id: I144b61af446b48a32786da8618aea4714e4dd62a
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/261545
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Herb Derby <herb@google.com>
2 files changed