Remove stale commented-out DCHECK

This DCHECK was commented out in Apr 2014
(https://chromium.googlesource.com/chromium/src/+/8a343ad96e4ca48eb665a77a6db8beb4357fe67c)
because it was causing Chrome OS test failures. Since this assertion has been
ignored for 2.5 years and the logic in this part of the code has since changed,
it is not clear that this assertion would be useful if it were ever re-enabled.

BUG=365507

Review-Url: https://codereview.chromium.org/2390803004
Cr-Commit-Position: refs/heads/master@{#422733}

third_party/WebKit/Source/core/animation/css/CSSAnimations.cpp

@@ -756,16 +756,8 @@ void CSSAnimations::calculateTransitionUpdate(CSSAnimationUpdate& update,
                         : nullptr;
   const CSSTransitionData* transitionData = style.transitions();
 
-#if DCHECK_IS_ON()
-  // In debug builds we verify that it would have been safe to avoid populating
-  // and testing listedProperties if the style recalc is due to animation.
-  const bool animationStyleRecalc = false;
-#else
-  // In release builds we avoid the cost of checking for new and interrupted
-  // transitions if the style recalc is due to animation.
   const bool animationStyleRecalc =
       elementAnimations && elementAnimations->isAnimationStyleChange();
-#endif
 
   std::bitset<numCSSProperties> listedProperties;
   bool anyTransitionHadTransitionAll = false;
@@ -825,11 +817,6 @@ void CSSAnimations::calculateTransitionUpdate(CSSAnimationUpdate& update,
       CSSPropertyID id = entry.key;
       if (!anyTransitionHadTransitionAll && !animationStyleRecalc &&
           !listedProperties.test(id - firstCSSProperty)) {
-        // TODO(crbug.com/365507): Figure out why this fails on Chrome OS login
-        // page.
-        // DCHECK(animation.playStateInternal() == Animation::Finished ||
-        //       !(elementAnimations &&
-        //         elementAnimations->isAnimationStyleChange()));
         update.cancelTransition(id);
       } else if (entry.value.animation->finishedInternal()) {
         update.finishTransition(id);