Implement the palette help and options buttons.

ash/common/system/chromeos/palette/palette_tray.h

Index: ash/common/system/chromeos/palette/palette_tray.h
diff --git a/ash/common/system/chromeos/palette/palette_tray.h b/ash/common/system/chromeos/palette/palette_tray.h
index dcd387cffe49a9b222d434747f214f47bff24da3..18d900ab1bc31f3f6a8337343b9d0a6aa7f2578b 100644
--- a/ash/common/system/chromeos/palette/palette_tray.h
+++ b/ash/common/system/chromeos/palette/palette_tray.h
@@ -50,6 +50,9 @@ class ASH_EXPORT PaletteTray : public TrayBackgroundView,
   void SetShelfAlignment(ShelfAlignment alignment) override;
   void AnchorUpdated() override;
 
+  // PaletteToolManager::Delegate:
+  void HidePalette() override;
+
  private:
   // views::TrayBubbleView::Delegate:
   void BubbleViewDestroyed() override;
@@ -66,7 +69,6 @@ class ASH_EXPORT PaletteTray : public TrayBackgroundView,
   void HideBubble(const views::TrayBubbleView* bubble_view) override;
 
   // PaletteToolManager::Delegate:
-  void HidePalette() override;
   void OnActiveToolChanged() override;
   WmWindow* GetWindow() override;