Removed leftover FIXME for whitespace attachment.

WhitespaceAttacher now handles this properly and it's done as part of
layout tree building, not style recalc.

Change-Id: I0fd970c86425c155429c008afdf280866b539a72
Reviewed-on: https://chromium-review.googlesource.com/626301Reviewed-by: Morten Stenshorne <mstensho@opera.com>
Commit-Queue: Rune Lillesveen <rune@opera.com>
Cr-Commit-Position: refs/heads/master@{#496438}

third_party/WebKit/Source/core/dom/Element.cpp

@@ -3426,8 +3426,7 @@ void Element::UpdatePseudoElement(PseudoId pseudo_id,
       MutableComputedStyle()->RemoveCachedPseudoStyle(pseudo_id);
 
     // PseudoElement styles hang off their parent element's style so if we
-    // needed a style recalc we should Force one on the pseudo.  FIXME: We
-    // should figure out the right text sibling to pass.
+    // needed a style recalc we should Force one on the pseudo.
     element->RecalcStyle(change == kUpdatePseudoElements ? kForce : change);
 
     // Wait until our parent is not displayed or