Refactor AddScrollListItem() in system menu detailed views

ash/system/audio/audio_detailed_view.h

Index: ash/system/audio/audio_detailed_view.h
diff --git a/ash/system/audio/audio_detailed_view.h b/ash/system/audio/audio_detailed_view.h
index 5e2d3fde02a55117927f8c25e7b7cb6bcd4c2fbc..7478ba8220c35e7a44f6b7856dfece4b65c21a99 100644
--- a/ash/system/audio/audio_detailed_view.h
+++ b/ash/system/audio/audio_detailed_view.h
@@ -15,13 +15,7 @@ namespace gfx {
 struct VectorIcon;
 }
 
-namespace views {
-class View;
-}
-
 namespace ash {
-class HoverHighlightView;
-
 namespace tray {
 
 class AudioDetailedView : public TrayDetailsView {
@@ -33,15 +27,9 @@ class AudioDetailedView : public TrayDetailsView {
   void Update();
 
  private:
-  // Helper functions to add non-clickable header rows within the scrollable
+  // Helper function to add non-clickable header rows within the scrollable
   // list.
-  void AddInputHeader();
-  void AddOutputHeader();
-  void AddScrollListInfoItem(int text_id, const gfx::VectorIcon& icon);
-
-  HoverHighlightView* AddScrollListItem(const base::string16& text,
-                                        bool highlight,
-                                        bool checked);
+  void AddAudioSubHeader(const gfx::VectorIcon& icon, int text_id);
 
   void CreateItems();