Enable compilation of //components/autofill on iOS with gn.

components/autofill/ios/browser/autofill_field_trial_ios.h

-// Copyright 2015 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_IOS_BROWSER_AUTOFILL_FIELD_TRIAL_IOS_H_
-#define COMPONENTS_AUTOFILL_IOS_BROWSER_AUTOFILL_FIELD_TRIAL_IOS_H_
-
-#include "base/macros.h"
-
-namespace autofill {
-
-// This class manages the iOS Autofill field trials.
-class AutofillFieldTrialIOS {
- public:
-  // Returns whether the user is in a full-form Autofill field trial. Full-form
-  // Autofill fills all fields of the form at once, similar to the desktop and
-  // Clank Autofill implementations. Previous iOS implementation requires user
-  // to select an Autofill value for each field individually, automatically
-  // advancing focus to the next field after each selection.
-  static bool IsFullFormAutofillEnabled();
-
- private:
-  DISALLOW_IMPLICIT_CONSTRUCTORS(AutofillFieldTrialIOS);
-};
-
-}  // namespace autofill
-
-#endif  // COMPONENTS_AUTOFILL_IOS_BROWSER_AUTOFILL_FIELD_TRIAL_IOS_H_