Reorder the AnimatedPropertyType enumeration

By moving AnimatedUnknown first (giving it the ordinal value 0), we can
simplify SVGElement::animatedPropertyTypeForCSSAttribute by removing
the contains() call (avoiding a double hash/lookup for the common case.)

Review-Url: https://codereview.chromium.org/2288583002
Cr-Commit-Position: refs/heads/master@{#415069}
2 files changed