[Autofill] Add Chrome flag that annotates web forms with form and field signatures

components/autofill/core/common/autofill_switches.h

 // Copyright 2013 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.
 
 #ifndef COMPONENTS_AUTOFILL_CORE_COMMON_AUTOFILL_SWITCHES_H_
 #define COMPONENTS_AUTOFILL_CORE_COMMON_AUTOFILL_SWITCHES_H_
 
 #include "build/build_config.h"
 
 namespace autofill {
 namespace switches {
 
 // All switches in alphabetical order. The switches should be documented
 // alongside the definition of their values in the .cc file.
 extern const char kDisableOfferStoreUnmaskedWalletCards[];
 extern const char kDisableOfferUploadCreditCards[];
 extern const char kDisablePasswordGeneration[];
 extern const char kDisableSingleClickAutofill[];
 extern const char kEnableOfferStoreUnmaskedWalletCards[];
 extern const char kEnableOfferUploadCreditCards[];
 extern const char kEnablePasswordGeneration[];
 extern const char kEnableSingleClickAutofill[];
 extern const char kEnableSuggestionsWithSubstringMatch[];
 extern const char kIgnoreAutocompleteOffForAutofill[];
 extern const char kLocalHeuristicsOnlyForPasswordGeneration[];
 extern const char kShowAutofillTypePredictions[];
+extern const char kShowAutofillSignatures[];
 extern const char kWalletServiceUseSandbox[];
 
 #if defined(OS_ANDROID)
 extern const char kDisableAccessorySuggestionView[];
 extern const char kEnableAccessorySuggestionView[];
 #endif  // defined(OS_ANDROID)
 
 }  // namespace switches
 }  // namespace autofill
 
 #endif  // COMPONENTS_AUTOFILL_CORE_COMMON_AUTOFILL_SWITCHES_H_