Add pref to enable/disable palette tray.

chrome/browser/extensions/api/settings_private/prefs_util.cc

 // Copyright 2015 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.
 
 #include "chrome/browser/extensions/api/settings_private/prefs_util.h"
 
 #include "build/build_config.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/extensions/chrome_extension_function.h"
 #include "chrome/browser/profiles/profile.h"
@@ skipping 239 matching lines @@
   (*s_whitelist)["settings.internet.wake_on_wifi_darkconnect"] =
       settings_private::PrefType::PREF_TYPE_BOOLEAN;
   (*s_whitelist)["settings.enable_screen_lock"] =
       settings_private::PrefType::PREF_TYPE_BOOLEAN;
 
   // Input method settings.
   (*s_whitelist)["settings.language.preload_engines"] =
       settings_private::PrefType::PREF_TYPE_STRING;
   (*s_whitelist)["settings.language.enabled_extension_imes"] =
       settings_private::PrefType::PREF_TYPE_STRING;
+  (*s_whitelist)["settings.enable_ash_palette"] =
+      settings_private::PrefType::PREF_TYPE_BOOLEAN;
   (*s_whitelist)["settings.launch_note_app_on_eject_event"] =
       settings_private::PrefType::PREF_TYPE_BOOLEAN;
 
   // Device settings.
   (*s_whitelist)["settings.touchpad.enable_tap_to_click"] =
       settings_private::PrefType::PREF_TYPE_BOOLEAN;
   (*s_whitelist)["settings.touchpad.natural_scroll"] =
       settings_private::PrefType::PREF_TYPE_BOOLEAN;
   (*s_whitelist)["settings.touchpad.sensitivity2"] =
       settings_private::PrefType::PREF_TYPE_NUMBER;
@@ skipping 382 matching lines @@
 
 bool PrefsUtil::IsCrosSetting(const std::string& pref_name) {
 #if defined(OS_CHROMEOS)
   return CrosSettings::Get()->IsCrosSettings(pref_name);
 #else
   return false;
 #endif
 }
 
 }  // namespace extensions