[ios] Adds LocationBarCoordinator.

ios/clean/chrome/browser/ui/omnibox/location_bar_mediator.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 IOS_CLEAN_CHROME_BROWSER_UI_OMNIBOX_LOCATION_BAR_MEDIATOR_H_
+#define IOS_CLEAN_CHROME_BROWSER_UI_OMNIBOX_LOCATION_BAR_MEDIATOR_H_
+
+#import <Foundation/Foundation.h>
+#include <memory>
+
+#import "ios/shared/chrome/browser/ui/omnibox/location_bar_delegate.h"
+
+class LocationBarController;
+class WebStateList;
+
+// LocationBarMediator listens for notifications from various models and updates
+// the UI accordingly.  Unlike other mediators in the new architecture,
+// LocationBarMediator is constrained to operate within the confines of the
+// cross-platform omnibox component.  Specifically, LocationBarMediator does not
+// have a |consumer| property, but rather it updates the UI through methods on
+// LocationBarController and OmniboxViewIOS.
+@interface LocationBarMediator : NSObject<LocationBarDelegate>
+
+- (instancetype)initWithWebStateList:(WebStateList*)webStateList
+    NS_DESIGNATED_INITIALIZER;
+
+- (instancetype)init NS_UNAVAILABLE;
+
+// Sets the LocationBarController that this mediator should use when updating
+// UI.  Unlike other mediators in the new architecture, LocationBarMediator
+// updates the UI through this LocationBarController object rather than through
+// a consumer.
+- (void)setLocationBar:(std::unique_ptr<LocationBarController>)locationBar;
+
+@end
+
+#endif  // IOS_CLEAN_CHROME_BROWSER_UI_OMNIBOX_LOCATION_BAR_MEDIATOR_H_