Web Animations CSS: Fix DocumentTimeline::numberOfActiveAnimationsForTesting()

Source/core/animation/DocumentTimeline.cpp

Index: Source/core/animation/DocumentTimeline.cpp
diff --git a/Source/core/animation/DocumentTimeline.cpp b/Source/core/animation/DocumentTimeline.cpp
index b3b7d08b93dcba629baae80b9b1073f6d829363f..3827b35d36365ff4e97c530bd961fb0db71ed437 100644
--- a/Source/core/animation/DocumentTimeline.cpp
+++ b/Source/core/animation/DocumentTimeline.cpp
@@ -158,7 +158,14 @@ size_t DocumentTimeline::numberOfActiveAnimationsForTesting() const
 {
     // Includes all players whose directly associated timed items
     // are current or in effect.
-    return isNull(m_zeroTime) ? 0 : m_players.size();
+    if (isNull(m_zeroTime))
+        return 0;
+    size_t count = 0;
+    for (size_t i = 0; i < m_players.size(); ++i) {
+        const TimedItem* timedItem = m_players[i]->source();
+        count += (timedItem && (timedItem->isCurrent() || timedItem->isInEffect()));
+    }
+    return count;
 }
 
 } // namespace