Web Animations: Set the DocumentTimeline's zero time when the Document reaches the 'loading' phase

Source/core/dom/Document.cpp

Index: Source/core/dom/Document.cpp
diff --git a/Source/core/dom/Document.cpp b/Source/core/dom/Document.cpp
index 0120ecbfce62f2123cafdf8a7667c875ace03d6c..d73a29ee99371896a3603c6b81f175a6c5a50f56 100644
--- a/Source/core/dom/Document.cpp
+++ b/Source/core/dom/Document.cpp
@@ -1084,15 +1084,15 @@ void Document::setReadyState(ReadyState readyState)
 
     switch (readyState) {
     case Loading:
-        if (!m_documentTiming.domLoading)
+        if (!m_documentTiming.domLoading) {
             m_documentTiming.domLoading = monotonicallyIncreasingTime();
+            if (RuntimeEnabledFeatures::webAnimationsEnabled())
+                m_timeline->setZeroTimeAsPerfTime(m_documentTiming.domLoading);
+        }
         break;
     case Interactive:
-        if (!m_documentTiming.domInteractive) {
+        if (!m_documentTiming.domInteractive)
             m_documentTiming.domInteractive = monotonicallyIncreasingTime();
-            if (RuntimeEnabledFeatures::webAnimationsEnabled())
-                m_timeline->setZeroTimeAsPerfTime(m_documentTiming.domInteractive);
-        }
         break;
     case Complete:
         if (!m_documentTiming.domComplete)