Bug 1360508: Adjust text-combine properly. r=jryans

Text style is always resolved via ServoStyleSet::ResolveStyleForText, either
from the frame constructor initially, or from
ServoRestyleManager::ProcessPostTraversalForText.

So text-only adjustments should go there instead. Since that doesn't call into
cascade(), all the code that passes `pseudo` there is dead code we can remove.

MozReview-Commit-ID: jpbBYpLlUL
Signed-off-by: Emilio Cobos Álvarez <emilio@crisal.io>

components/style/animation.rs

@@ -461,7 +461,6 @@ fn compute_style_for_animation_step(context: &SharedStyleContext,
             let computed =
                 properties::apply_declarations(&context.stylist.device,
                                                /* is_root = */ false,
-                                               /* pseudo = */ None,
                                                iter,
                                                previous_style,
                                                previous_style,