Extensions: create a simple model for the browser action buttons toolstrip an...

chrome/browser/extensions/extension_toolbar_model.h

+// Copyright (c) 2009 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_EXTENSIONS_EXTENSION_TOOLBAR_MODEL_H_
+#define CHROME_BROWSER_EXTENSIONS_EXTENSION_TOOLBAR_MODEL_H_
+
+#include "base/observer_list.h"
+#include "chrome/common/extensions/extension.h"
+#include "chrome/common/notification_observer.h"
+#include "chrome/common/notification_registrar.h"
+
+class ExtensionsService;
+
+// Model for the browser actions toolbar.
+class ExtensionToolbarModel : public NotificationObserver {
+ public:
+  explicit ExtensionToolbarModel(ExtensionsService* service);
+  ~ExtensionToolbarModel();
+
+  // A class which is informed of changes to the model; represents the view of
+  // MVC.
+  class Observer {
+   public:
+    // An extension with a browser action button has been added, and should go
+    // in the toolbar at |index|.
+    virtual void BrowserActionAdded(Extension* extension, int index) {}
+
+    // The browser action button for |extension| should no longer show.
+    virtual void BrowserActionRemoved(Extension* extension) {}
+  };
+
+  void AddObserver(Observer* observer);
+  void RemoveObserver(Observer* observer);
+
+  ExtensionList::iterator begin() {
+    return toolitems_.begin();
+  }
+
+  ExtensionList::iterator end() {
+    return toolitems_.end();
+  }
+
+ private:
+  // NotificationObserver implementation.
+  virtual void Observe(NotificationType type,
+                       const NotificationSource& source,
+                       const NotificationDetails& details);
+
+  // Our observers.
+  ObserverList<Observer> observers_;
+
+  void AddExtension(Extension* extension);
+  void RemoveExtension(Extension* extension);
+
+  // Our ExtensionsService, guaranteed to outlive us.
+  ExtensionsService* service_;
+
+  // Ordered list of browser action buttons.
+  ExtensionList toolitems_;
+
+  NotificationRegistrar registrar_;
+};
+#endif  // CHROME_BROWSER_EXTENSIONS_EXTENSION_TOOLBAR_MODEL_H_