Upstream Chrome on iOS source code [9/11].

ios/chrome/browser/ui/toolbar/tools_menu_button_observer_bridge.h

+// Copyright 2016 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_CHROME_BROWSER_UI_TOOLBAR_TOOLS_MENU_BUTTON_OBSERVER_BRIDGE_H_
+#define IOS_CHROME_BROWSER_UI_TOOLBAR_TOOLS_MENU_BUTTON_OBSERVER_BRIDGE_H_
+
+#import <UIKit/UIKit.h>
+
+#import "base/mac/scoped_nsobject.h"
+#include "components/reading_list/ios/reading_list_model_observer.h"
+
+@class ToolbarToolsMenuButton;
+
+// C++ bridge informing a ToolbarToolsMenuButton whether the Reading List Model
+// contains unread items.
+class ToolsMenuButtonObserverBridge : public ReadingListModelObserver {
+ public:
+  // Creates the bridge to the ToolbarToolsMenuButton |button|.
+  ToolsMenuButtonObserverBridge(ReadingListModel* readingListModel,
+                                ToolbarToolsMenuButton* button);
+
+  ~ToolsMenuButtonObserverBridge() final;
+
+  // ReadingListModelObserver implementation.
+  void ReadingListModelLoaded(const ReadingListModel* model) override;
+  void ReadingListDidApplyChanges(ReadingListModel* model) override;
+
+ private:
+  // Notify the ToolbarToolsMenuButton of whether the reading list contains
+  // unread items.
+  void UpdateButtonWithModel(const ReadingListModel* model);
+  ReadingListModel* readingListModel_;
+  base::scoped_nsobject<ToolbarToolsMenuButton> button_;
+};
+
+#endif  // IOS_CHROME_BROWSER_UI_TOOLBAR_TOOLS_MENU_BUTTON_OBSERVER_BRIDGE_H_