Implement all system menu title row buttons for Ash MD

ash/common/system/tray_accessibility.h

Index: ash/common/system/tray_accessibility.h
diff --git a/ash/common/system/tray_accessibility.h b/ash/common/system/tray_accessibility.h
index b0378bf3e2f279d56c5a114d8b7687f4f76dfff4..a92ceb17cd16bfc0183fc0f5044b7eba011dd18d 100644
--- a/ash/common/system/tray_accessibility.h
+++ b/ash/common/system/tray_accessibility.h
@@ -64,7 +64,13 @@ class AccessibilityDetailedView : public TrayDetailsView,
   void HandleViewClicked(views::View* view) override;
   void HandleButtonPressed(views::Button* sender,
                            const ui::Event& event) override;
-  void ShowSettings() override;
+  void CreateExtraTitleRowButtons() override;
+
+  // Launches the WebUI settings in a browser and closes the system menu.
+  void ShowSettings();
+
+  // Launches the a11y help article in a browser and closes the system menu.
+  void ShowHelp();
 
   // Add the accessibility feature list.
   void AppendAccessibilityList();