Only use shader-based rounded corners for cases supported by the shader.

In particular, each corner needs to be circular, and radii need to be
less than min(width, height).

Bug: 966488

Change-Id: If287dc93bbd30eca2d51fb2558402ef4fcb647ec
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1628327
Commit-Queue: Chris Harrelson <chrishtr@chromium.org>
Reviewed-by: Mason Freed <masonfreed@chromium.org>
Cr-Commit-Position: refs/heads/master@{#663338}
18 files changed