Make calls to AtomicString(const String&) explicit in html/

Source/core/html/track/TextTrackCue.cpp

Index: Source/core/html/track/TextTrackCue.cpp
diff --git a/Source/core/html/track/TextTrackCue.cpp b/Source/core/html/track/TextTrackCue.cpp
index cfb2effe24b7cd190c465bce786325e6030b860f..a89b46299beec8a669fe564ad6cb41860f6ddf18 100644
--- a/Source/core/html/track/TextTrackCue.cpp
+++ b/Source/core/html/track/TextTrackCue.cpp
@@ -83,7 +83,7 @@ void TextTrackCue::setTrack(TextTrack* track)
     m_track = track;
 }
 
-void TextTrackCue::setId(const String& id)
+void TextTrackCue::setId(const AtomicString& id)
 {
     if (m_id == id)
         return;