Add pref to enable/disable palette tray.

chrome/common/pref_names.h

 // Copyright (c) 2012 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.
 
 // Constants for the names of various preferences, for easier changing.
 
 #ifndef CHROME_COMMON_PREF_NAMES_H_
 #define CHROME_COMMON_PREF_NAMES_H_
 
 #include <stddef.h>
@@ skipping 225 matching lines @@
 extern const char kLabsMediaplayerEnabled[];
 extern const char kEnableAutoScreenLock[];
 extern const char kShow3gPromoNotification[];
 extern const char kDataSaverPromptsShown[];
 extern const char kChromeOSReleaseNotesVersion[];
 extern const char kUseSharedProxies[];
 extern const char kDisplayPowerState[];
 extern const char kDisplayProperties[];
 extern const char kSecondaryDisplays[];
 extern const char kDisplayRotationLock[];
+extern const char kEnableAshPalette[];
 extern const char kLaunchNoteAppOnEjectEvent[];
 extern const char kSessionUserActivitySeen[];
 extern const char kSessionStartTime[];
 extern const char kSessionLengthLimit[];
 extern const char kSessionWaitForInitialUserActivity[];
 extern const char kPowerAcScreenDimDelayMs[];
 extern const char kPowerAcScreenOffDelayMs[];
 extern const char kPowerAcScreenLockDelayMs[];
 extern const char kPowerAcIdleWarningDelayMs[];
 extern const char kPowerAcIdleDelayMs[];
@@ skipping 572 matching lines @@
 extern const char kMediaRouterFirstRunFlowAcknowledged[];
 extern const char kMediaRouterAlwaysShowActionIcon[];
 #endif
 
 extern const char kOriginTrialPublicKey[];
 extern const char kOriginTrialDisabledFeatures[];
 
 }  // namespace prefs
 
 #endif  // CHROME_COMMON_PREF_NAMES_H_