Add Now setting and migration logic.

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 573 matching lines @@
 extern const char kWebAppCreateInQuickLaunchBar[];
 
 extern const char kGeolocationAccessToken[];
 #if defined(OS_ANDROID)
 extern const char kGeolocationEnabled[];
 #endif
 
 #if defined(ENABLE_GOOGLE_NOW)
 extern const char kGoogleGeolocationAccessEnabled[];
 #endif
+extern const char kGoogleNowLauncherEnabled[];
 
 extern const char kDefaultAudioCaptureDevice[];
 extern const char kDefaultVideoCaptureDevice[];
 extern const char kMediaDeviceIdSalt[];
 
 extern const char kPrintPreviewStickySettings[];
 extern const char kCloudPrintRoot[];
 extern const char kCloudPrintDialogWidth[];
 extern const char kCloudPrintDialogHeight[];
 extern const char kCloudPrintSigninDialogWidth[];
@@ skipping 214 matching lines @@
 
 extern const char kRegisteredSupervisedUserWhitelists[];
 
 #if defined(ENABLE_EXTENSIONS)
 extern const char kAnimationPolicy[];
 #endif
 
 }  // namespace prefs
 
 #endif  // CHROME_COMMON_PREF_NAMES_H_