[CRD iOS] Branching internal and external implementations

remoting/ios/app/app_view_controller.h

+// Copyright 2017 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 REMOTING_IOS_APP_APP_VIEW_CONTROLLER_H_
+#define REMOTING_IOS_APP_APP_VIEW_CONTROLLER_H_
+
+#import <UIKit/UIKit.h>
+
+@protocol AppController<NSObject>
+
+// For adding new methods, please mark them as optional until they are
+// implemented in both Chromium and ios_internal. For deletion, just reverse the
+// procedure. This is to prevent build break in internal buildbot.
+
+- (void)showMenuAnimated:(BOOL)animated;
+- (void)hideMenuAnimated:(BOOL)animated;
+- (void)presentSignInFlow;
+
+@end
+
+// The root view controller of the app. It acts as a container controller for
+// |mainViewController|, which will be shown as the primary content of the view.
+// Implementation can add drawer or modal for things like the side menu or help
+// and feedback.
+@interface AppViewController : UIViewController<AppController>
+
+- (instancetype)initWithMainViewController:
+    (UIViewController*)mainViewController;
+
+@end
+
+#endif  // REMOTING_IOS_APP_APP_VIEW_CONTROLLER_H_