Add a policy to re-enable deprecated web platform features.

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 337 matching lines @@
 extern const char kAutofillDialogPayWithoutWallet[];
 extern const char kAutofillDialogWalletLocationAcceptance[];
 extern const char kAutofillDialogSaveData[];
 extern const char kAutofillDialogWalletShippingSameAsBilling[];
 extern const char kAutofillGeneratedCardBubbleTimesShown[];
 extern const char kAutofillDialogDefaults[];
 
 extern const char kPinnedTabs[];
 
 extern const char kDisable3DAPIs[];
+extern const char kEnableDeprecatedWebPlatformFeatures[];
 extern const char kEnableHyperlinkAuditing[];
 extern const char kEnableReferrers[];
 extern const char kEnableDoNotTrack[];
 
 extern const char kImportBookmarks[];
 extern const char kImportHistory[];
 extern const char kImportHomepage[];
 extern const char kImportSearchEngine[];
 extern const char kImportSavedPasswords[];
 
@@ skipping 463 matching lines @@
 
 #if defined(OS_ANDROID)
 extern const char kPartnerBookmarkMappings[];
 #endif
 
 extern const char kQuickCheckEnabled[];
 
 }  // namespace prefs
 
 #endif  // CHROME_COMMON_PREF_NAMES_H_