Remove the very old code that migrated password data from the WebDataService to PasswordStore.

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_
 #pragma once
 
@@ skipping 551 matching lines @@
 extern const char kProfileGAIAInfoPictureURL[];
 
 extern const char kWebAppCreateOnDesktop[];
 extern const char kWebAppCreateInAppsMenu[];
 extern const char kWebAppCreateInQuickLaunchBar[];
 
 extern const char kGeolocationAccessToken[];
 extern const char kGeolocationDefaultContentSetting[];
 extern const char kGeolocationContentSettings[];
 
-extern const char kLoginDatabaseMigrated[];
-
 extern const char kRemoteAccessHostFirewallTraversal[];
 
 extern const char kPrintingEnabled[];
 extern const char kPrintPreviewDisabled[];
 
 extern const char kCloudPrintServiceURL[];
 extern const char kCloudPrintSigninURL[];
 extern const char kCloudPrintDialogWidth[];
 extern const char kCloudPrintDialogHeight[];
 extern const char kCloudPrintSigninDialogWidth[];
@@ skipping 106 matching lines @@
 extern const char kPointsBufferedForVelocity[];
 extern const char kRailBreakProportion[];
 extern const char kRailStartProportion[];
 #endif
 
 extern const char kInManagedMode[];
 
 }  // namespace prefs
 
 #endif  // CHROME_COMMON_PREF_NAMES_H_