Convert enable_one_click_signin to new buildflag system

chrome/browser/ui/cocoa/browser_window_cocoa.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.
 
 #ifndef CHROME_BROWSER_UI_COCOA_BROWSER_WINDOW_COCOA_H_
 #define CHROME_BROWSER_UI_COCOA_BROWSER_WINDOW_COCOA_H_
 
 #include "base/mac/scoped_nsobject.h"
 #include "base/memory/weak_ptr.h"
 #include "chrome/browser/extensions/extension_keybinding_registry.h"
 #include "chrome/browser/signin/chrome_signin_helper.h"
 #include "chrome/browser/ui/browser_window.h"
 #include "chrome/browser/ui/search/search_model_observer.h"
 #include "chrome/browser/ui/tabs/tab_utils.h"
+#include "chrome/common/features.h"
 #include "components/bookmarks/browser/bookmark_model.h"
 #include "components/security_state/security_state_model.h"
 #include "ui/base/ui_base_types.h"
 
 class Browser;
 @class BrowserWindowController;
 @class FindBarCocoaController;
 @class NSEvent;
 @class NSMenu;
 @class NSWindow;
@@ skipping 80 matching lines @@
       const WebApplicationInfo& web_app_info,
       const ShowBookmarkAppBubbleCallback& callback) override;
   autofill::SaveCardBubbleView* ShowSaveCreditCardBubble(
       content::WebContents* contents,
       autofill::SaveCardBubbleController* controller,
       bool user_gesture) override;
   void ShowTranslateBubble(content::WebContents* contents,
                            translate::TranslateStep step,
                            translate::TranslateErrors::Type error_type,
                            bool is_user_gesture) override;
-#if defined(ENABLE_ONE_CLICK_SIGNIN)
+#if BUILDFLAG(ENABLE_ONE_CLICK_SIGNIN)
   void ShowOneClickSigninBubble(
       OneClickSigninBubbleType type,
       const base::string16& email,
       const base::string16& error_message,
       const StartSyncCallback& start_sync_callback) override;
 #endif
   bool IsDownloadShelfVisible() const override;
   DownloadShelf* GetDownloadShelf() override;
   void ConfirmBrowserCloseWithPendingDownloads(
       int download_count,
@@ skipping 64 matching lines @@
   ui::WindowShowState initial_show_state_;
   NSInteger attention_request_id_;  // identifier from requestUserAttention
 
   // Preserves window media state to show appropriate icon in the window title
   // which can be audio playing, muting or none (determined by media state of
   // tabs.
   TabMediaState media_state_;
 };
 
 #endif  // CHROME_BROWSER_UI_COCOA_BROWSER_WINDOW_COCOA_H_