Generate ComputedStyle::hasViewportUnits and hasRemUnits.

This patch moves hasViewportUnits and hasRemUnits to be generated in
ComputedStyleBase. Both are noninherited nonproperties.

hasRemUnits is generated as a monotonic_flag field, but
hasViewportUnits needs to be a boolean flag field because there are
places where it gets set to false.

Since these are the two remaining noninherited fields stored directly
in ComputedStyle, this patch also removes the NonInheritedData struct
from ComputedStyle.

Diff of generated files:
https://gist.github.com/47fd74b4a54917d0413367227dcb962a/revisions

BUG=628043

Review-Url: https://codereview.chromium.org/2797963002
Cr-Commit-Position: refs/heads/master@{#462377}
3 files changed