Convert --{enable,disable}-simplified-fullscreen-ui to a feature flag.

chrome/browser/ui/exclusive_access/exclusive_access_manager.h

 // Copyright (c) 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 CHROME_BROWSER_UI_EXCLUSIVE_ACCESS_EXCLUSIVE_ACCESS_MANAGER_H_
 #define CHROME_BROWSER_UI_EXCLUSIVE_ACCESS_EXCLUSIVE_ACCESS_MANAGER_H_
 
+#include "base/feature_list.h"
 #include "base/macros.h"
 #include "base/memory/scoped_ptr.h"
 #include "chrome/browser/ui/exclusive_access/exclusive_access_bubble_type.h"
 #include "chrome/browser/ui/exclusive_access/fullscreen_controller.h"
 #include "chrome/browser/ui/exclusive_access/mouse_lock_controller.h"
 
 class ExclusiveAccessContext;
 class FullscreenController;
 class GURL;
 class MouseLockController;
 
 namespace content {
 struct NativeWebKeyboardEvent;
 class WebContents;
 }
 
 // This class combines the different exclusive access modes (like fullscreen and
 // mouse lock) which are each handled by respective controller. It also updates
 // the exit bubble to reflect the combined state.
 class ExclusiveAccessManager {
  public:
+  // A new user experience for transitioning into fullscreen and mouse pointer
+  // lock states.
+  static const base::Feature kSimplifiedUIFeature;
+
   explicit ExclusiveAccessManager(
       ExclusiveAccessContext* exclusive_access_context);
   ~ExclusiveAccessManager();
 
   FullscreenController* fullscreen_controller() {
     return &fullscreen_controller_;
   }
 
   MouseLockController* mouse_lock_controller() {
     return &mouse_lock_controller_;
@@ skipping 29 matching lines @@
 
  private:
   ExclusiveAccessContext* const exclusive_access_context_;
   FullscreenController fullscreen_controller_;
   MouseLockController mouse_lock_controller_;
 
   DISALLOW_COPY_AND_ASSIGN(ExclusiveAccessManager);
 };
 
 #endif  // CHROME_BROWSER_UI_EXCLUSIVE_ACCESS_EXCLUSIVE_ACCESS_MANAGER_H_