Add pref entry for virtual keyboard

chrome/common/pref_names.h

 // Copyright (c) 2011 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_
 #pragma once
 
@@ skipping 148 matching lines @@
 extern const char kLanguageMozcUseNumberConversion[];
 extern const char kLanguageMozcUseHistorySuggest[];
 extern const char kLanguageMozcUseDictionarySuggest[];
 extern const char kLanguageMozcSuggestionsSize[];
 extern const char kLanguageXkbRemapSearchKeyTo[];
 extern const char kLanguageXkbRemapControlKeyTo[];
 extern const char kLanguageXkbRemapAltKeyTo[];
 extern const char kLanguageXkbAutoRepeatEnabled[];
 extern const char kLanguageXkbAutoRepeatDelay[];
 extern const char kLanguageXkbAutoRepeatInterval[];
+extern const char kLanguagePreferredVirtualKeyboard[];
 extern const char kAccessibilityEnabled[];
 extern const char kLabsAdvancedFilesystemEnabled[];
 extern const char kLabsMediaplayerEnabled[];
 extern const char kEnableScreenLock[];
 extern const char kShowPlanNotifications[];
 extern const char kShow3gPromoNotification[];
 extern const char kLastUsedFileBrowserHandlers[];
 extern const char kUseSharedProxies[];
 extern const char kOAuth1Token[];
 extern const char kOAuth1Secret[];
@@ skipping 350 matching lines @@
 extern const char kCustomHandlersEnabled[];
 
 extern const char kUserCreatedLoginItem[];
 extern const char kBackgroundModeEnabled[];
 
 extern const char kDevicePolicyRefreshRate[];
 extern const char kUserPolicyRefreshRate[];
 }  // namespace prefs
 
 #endif  // CHROME_COMMON_PREF_NAMES_H_