Clamp out of range calc() values after font-style: oblique calc(...)

This fixes the bug referenced [here.]
(https://bugs.chromium.org/p/chromium/issues/detail?id=809943)

Values specified in a calc() function after an oblique now clamp to the
range of [-90, 90].

https://www.w3.org/TR/css-fonts-4/ - Restricts values to -90-90
https://drafts.csswg.org/css-values-3/#calc-range - Requires that the
results of Calc be clamped.

Bug: 809943
Change-Id: I474f034fc87018bf983c89fba52ed4a09994f924
Reviewed-on: https://chromium-review.googlesource.com/c/1410177
Commit-Queue: Dominik Röttsches <drott@chromium.org>
Commit-Queue: Sushanth Rajasankar <Sushraja@microsoft.com>
Reviewed-by: Dominik Röttsches <drott@chromium.org>
Reviewed-by: Rune Lillesveen <futhark@chromium.org>
Cr-Commit-Position: refs/heads/master@{#623808}
9 files changed