Check explicitly for style invalidation/recalc in @font-face test.

needsLayoutTreeUpdate will return true for needing to update the global
ruleset for async style update. Even if the test only tries to add a
@font-face rule, we unconditionally recollect the CSSGlobalRuleSet when
stylesheets are added or removed.

Instead check that adding a @font-face rule in a shadow tree does not
cause style invalidation or recalc.

Cr-Commit-Position: refs/heads/master@{#434367}
1 file changed