Add timelineOffset() support to WebMediaPlayerAndroid.

content/renderer/media/android/webmediaplayer_android.cc

Index: content/renderer/media/android/webmediaplayer_android.cc
diff --git a/content/renderer/media/android/webmediaplayer_android.cc b/content/renderer/media/android/webmediaplayer_android.cc
index c8c8ae454c14feef27ceab641037b8144d3c2d83..6ad72da077aa8c706b3f94d0e9218a1d9c19b5bc 100644
--- a/content/renderer/media/android/webmediaplayer_android.cc
+++ b/content/renderer/media/android/webmediaplayer_android.cc
@@ -397,6 +397,17 @@ double WebMediaPlayerAndroid::duration() const {
   return duration_.InSecondsF();
 }
 
+double WebMediaPlayerAndroid::timelineOffset() const {
+  base::Time timeline_offset;
+  if (media_source_delegate_)
+    timeline_offset = media_source_delegate_->GetTimelineOffset();
+
+  if (timeline_offset.is_null())
+    return std::numeric_limits<double>::quiet_NaN();
+
+  return timeline_offset.ToJsTime();
+}
+
 double WebMediaPlayerAndroid::currentTime() const {
   // If the player is processing a seek, return the seek time.
   // Blink may still query us if updatePlaybackState() occurs while seeking.