Add links to more options pages for Chrome OS accessibility features

chrome/browser/ui/webui/settings/chromeos/accessibility_handler.h

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_BROWSER_UI_WEBUI_SETTINGS_CHROMEOS_ACCESSIBILITY_HANDLER_H_
 #define CHROME_BROWSER_UI_WEBUI_SETTINGS_CHROMEOS_ACCESSIBILITY_HANDLER_H_
 
 #include "base/macros.h"
 #include "chrome/browser/ui/webui/settings/settings_page_ui_handler.h"
 
@@ skipping 14 matching lines @@
  public:
   explicit AccessibilityHandler(content::WebUI* webui);
   ~AccessibilityHandler() override;
 
   // SettingsPageUIHandler implementation.
   void RegisterMessages() override;
   void OnJavascriptAllowed() override {}
   void OnJavascriptDisallowed() override {}
 
  private:
-  // Callback for the "showChromeVoxSettings" message.
+  // Callback for the messages to show settings for ChromeVox,
+  // Select To Speak, or Switch Access.
   void HandleShowChromeVoxSettings(const base::ListValue* args);
+  void HandleShowSelectToSpeakSettings(const base::ListValue* args);
+  void HandleShowSwitchAccessSettings(const base::ListValue* args);
+
+  void OpenExtensionOptionsPage(const char extension_id[]);
 
   Profile* profile_;  // Weak pointer.
 
   DISALLOW_COPY_AND_ASSIGN(AccessibilityHandler);
 };
 
 }  // namespace settings
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_UI_WEBUI_SETTINGS_CHROMEOS_ACCESSIBILITY_HANDLER_H_