[skottie] Clamp SkCubicMap results to [0,1]

Looks like SkCubicMap can produce slightly out-of-range values.

That's prolly some unimportant precision artifact, but since we're
asserting t is in [0,1] down the line it'd be nice to not crash in debug.

TBR=

Change-Id: I048b691d1c0f0977556d5b25893a6dab2b9986cc
Reviewed-on: https://skia-review.googlesource.com/102480
Reviewed-by: Florin Malita <fmalita@chromium.org>
Commit-Queue: Florin Malita <fmalita@chromium.org>
1 file changed