The correct ordering of properties depends on the type of style map:

- Computed: css properties first, then vendor prefixed ones, then
  custom properties. Within each category, sort by code point.
- Inline: same order as the CSSStyleDeclaration.
- Declared: same order as the CSSRule.

Spec: https://drafts.css-houdini.org/css-typed-om-1/#stylepropertymapreadonly

Bug: 545318
Change-Id: I34fe8f0741bdcc2188926b37635672a4dda32625
Reviewed-on: https://chromium-review.googlesource.com/940381
Commit-Queue: Darren Shen <[email protected]>
Reviewed-by: nainar <[email protected]>
Cr-Commit-Position: refs/heads/master@{#540066}