merge_pr_9366
CSSUnitValue.unit should be immutable to prevent cyclic references Bug: 803687 Change-Id: I35f79ec2491277fcb2d02ce85a2e9c6ecd8c3a07 Reviewed-on: https://chromium-review.googlesource.com/897177 Reviewed-by: Darren Shen <[email protected]> Commit-Queue: Hwanseung Lee <[email protected]> Cr-Commit-Position: refs/heads/master@{#534237}