MD History: promote menu button to show clear browsing data in narrow mode

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 288 matching lines @@
 extern const char kQuickUnlockPinSalt[];
 extern const char kQuickUnlockPinSecret[];
 extern const char kEolStatus[];
 extern const char kEolNotificationDismissed[];
 extern const char kQuickUnlockFeatureNotificationShown[];
 #endif  // defined(OS_CHROMEOS)
 extern const char kShowHomeButton[];
 extern const char kSpeechRecognitionFilterProfanities[];
 extern const char kSavingBrowserHistoryDisabled[];
 extern const char kAllowDeletingBrowserHistory[];
+#if !defined(OS_ANDROID) && !defined(OS_IOS)
+extern const char kMdHistoryMenuPromoShown[];
+#endif
 extern const char kForceGoogleSafeSearch[];
 extern const char kForceYouTubeSafetyMode[];
 extern const char kForceSessionSync[];
 extern const char kAllowedDomainsForApps[];
 #if defined(OS_LINUX) && !defined(OS_CHROMEOS)
 extern const char kUsesSystemTheme[];
 #endif
 extern const char kCurrentThemePackFilename[];
 extern const char kCurrentThemeID[];
 extern const char kCurrentThemeImages[];
@@ skipping 508 matching lines @@
 #endif
 
 extern const char kOriginTrialPublicKey[];
 extern const char kOriginTrialDisabledFeatures[];
 
 extern const char kComponentUpdatesEnabled[];
 
 }  // namespace prefs
 
 #endif  // CHROME_COMMON_PREF_NAMES_H_