Make LogoutButtonTray a regular View

ash/system/palette/palette_tray.h

Index: ash/system/palette/palette_tray.h
diff --git a/ash/system/palette/palette_tray.h b/ash/system/palette/palette_tray.h
index 23a295a832fdcc25d015b524986b496aea95105d..c9074e456fae4316f256d57b7260c749d3763a7c 100644
--- a/ash/system/palette/palette_tray.h
+++ b/ash/system/palette/palette_tray.h
@@ -5,7 +5,6 @@
 #ifndef ASH_SYSTEM_PALETTE_PALETTE_TRAY_H_
 #define ASH_SYSTEM_PALETTE_PALETTE_TRAY_H_
 
-#include <map>
 #include <memory>
 
 #include "ash/ash_export.h"
@@ -58,7 +57,6 @@ class ASH_EXPORT PaletteTray : public TrayBackgroundView,
   void ClickedOutsideBubble() override;
   base::string16 GetAccessibleNameForTray() override;
   void HideBubbleWithView(const views::TrayBubbleView* bubble_view) override;
-  void SetShelfAlignment(ShelfAlignment alignment) override;
   void AnchorUpdated() override;
   void Initialize() override;