Add back HTMLMediaElement::m_lastTimeUpdateEventMovieTime.

Source/core/html/HTMLMediaElement.h

Index: Source/core/html/HTMLMediaElement.h
diff --git a/Source/core/html/HTMLMediaElement.h b/Source/core/html/HTMLMediaElement.h
index 2e0967169a9dfeb35047ad8f7c99ae6f54dd9530..952127af9810f8b87bdaac5f21a7f20db0e2a4ef 100644
--- a/Source/core/html/HTMLMediaElement.h
+++ b/Source/core/html/HTMLMediaElement.h
@@ -508,6 +508,9 @@ private:
     // The last time a timeupdate event was sent (wall clock).
     double m_lastTimeUpdateEventWallTime;
 
+    // The last time a timeupdate event was sent in movie time.
+    double m_lastTimeUpdateEventMovieTime;
+
     // The default playback start position.
     double m_defaultPlaybackStartPosition;