We can combine matchAuthorRulesForShadowHost into
matchAuthorRules, and also combine the two matchUARules
methods.
collectScopedResolversForHostedShadowTrees and the Vector
of ScopedStyleResolvers was also not needed. Sky can only
ever have two resolvers, the one for your scope, and the
one for your host rules.
R=ojan@chromium.org
Review URL: https://codereview.chromium.org/836193003