Perform color property application in CSSProperty classes.

This applies to:

  background-color
  border-bottom-color
  border-left-color
  border-right-color
  border-top-color
  column-rule-color
  outline-color
  text-decoration-color
  -webkit-text-emphasis-color
  -webkit-text-fill-color
  -webkit-text-stroke-color

R=futhark@chromium.org

      Style, _except_ background-color which is stored as a StyleColor.
      (I don't yet know why). This is the reason for using the
      custom_apply_args['initial_color'] instead of the regular
      'default_value' defined in CSSProperties.json5.

Note: All of the above properties are stored as a Color+1bit on Computed-
Bug: 751354
Change-Id: Icef9c99b3507da88820e4a79d6864f315f8b7136
Reviewed-on: https://chromium-review.googlesource.com/1061415
Reviewed-by: Rune Lillesveen <futhark@chromium.org>
Commit-Queue: Anders Ruud <andruud@chromium.org>
Cr-Commit-Position: refs/heads/master@{#559854}
6 files changed