Add small offset to t in GrLinearGradientLayout.

This works around a varying interpolation issue when a hard stop occurs
a along a row or column of pixel centers.

Bug: chromium:938592
Change-Id: I4c239b2831c3e901cbbfa43f0a60a3d7fb0fef75
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/200939
Reviewed-by: Michael Ludwig <michaelludwig@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>
2 files changed