Web Animations: Expose timeline currentTime in IDL

Source/core/animation/DocumentTimeline.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 126 matching lines @@
 {
     m_timer.stop();
 }
 
 void DocumentTimeline::DocumentTimelineTiming::serviceOnNextFrame()
 {
     if (m_timeline->m_document && m_timeline->m_document->view())
         m_timeline->m_document->view()->scheduleAnimation();
 }
 
+double DocumentTimeline::currentTime(bool& isNull)
+{
+    if (!m_document) {
+        isNull = true;
+        return std::numeric_limits<double>::quiet_NaN();
+    }
+    double result = m_document->animationClock().currentTime() - m_zeroTime;
+    isNull = std::isnan(result);
+    return result;
+}
+
 double DocumentTimeline::currentTime()
 {
-    if (!m_document)
-        return std::numeric_limits<double>::quiet_NaN();
-    return m_document->animationClock().currentTime() - m_zeroTime;
+    bool isNull;
+    return currentTime(isNull);
 }
 
 double DocumentTimeline::effectiveTime()
 {
     double time = currentTime();
     return std::isnan(time) ? 0 : time;
 }
 
 void DocumentTimeline::pauseAnimationsForTesting(double pauseTime)
 {
@@ skipping 25 matching lines @@
             count += (timedItem && (timedItem->isCurrent() || timedItem->isInEffect()));
     }
     return count;
 }
 
 void DocumentTimeline::detachFromDocument() {
     m_document = 0;
 }
 
 } // namespace