Create a cross-platform helper class for badging the wrench menu.

chrome/browser/ui/toolbar/wrench_menu_badge_controller.h

+// Copyright 2014 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_TOOLBAR_WRENCH_MENU_BADGE_CONTROLLER_H_
+#define CHROME_BROWSER_UI_TOOLBAR_WRENCH_MENU_BADGE_CONTROLLER_H_
+
+#include "base/macros.h"
+#include "chrome/browser/ui/toolbar/wrench_icon_painter.h"
+#include "content/public/browser/notification_details.h"
+#include "content/public/browser/notification_observer.h"
+#include "content/public/browser/notification_registrar.h"
+#include "content/public/browser/notification_service.h"
+
+class Profile;
+
+// WrenchMenuBadgeController encapsulates the logic for badging the wrench menu
+// icon as a result of various events - such as available updates, errors, etc.
+class WrenchMenuBadgeController : public content::NotificationObserver {
+ public:
+  enum BadgeType {

[sky, 2014/07/17 19:54:28]

nit: use enum names as described for content, eg BAGE_TYPE_NONE...

[Alexei Svitkine (slow), 2014/07/17 21:35:28]

Done.

+    NONE,
+    UPGRADE_NOTIFICATION,
+    GLOBAL_ERROR,
+    INCOMPATIBILITY_WARNING,
+  };
+
+  // Delegate interface for receiving badge update notifications.
+  class Delegate {
+   public:
+    // Notifies the UI to update the badge to have the specified |severity|, as
+    // well as specifying whether it should |animate|. The |type| parameter
+    // specifies the type of change (i.e. the source of the notification).
+    virtual void UpdateBadgeSeverity(BadgeType type,
+                                     WrenchIconPainter::Severity severity,
+                                     bool animate) = 0;
+  };

[sky, 2014/07/17 19:54:28]

add protected virtual constructor to make ownership clearer.

[Alexei Svitkine (slow), 2014/07/17 21:35:28]

Done.

+
+  // Creates an instance of this class for the given |profile| that will notify
+  // |delegate| of updates.
+  WrenchMenuBadgeController(Profile* profile, Delegate* delegate);
+  virtual ~WrenchMenuBadgeController();
+
+  // Forces an update of the UI based on the current state of the world. This
+  // will check whether there are any current pending updates, global errors,
+  // etc. and based on that information trigger an appropriate call to the
+  // delegate.
+  void UpdateDelegate();
+
+ private:
+  // content::NotificationObserver:
+  virtual void Observe(int type,
+                       const content::NotificationSource& source,
+                       const content::NotificationDetails& details) OVERRIDE;
+
+  Profile* profile_;
+  Delegate* delegate_;
+  content::NotificationRegistrar registrar_;
+
+  DISALLOW_COPY_AND_ASSIGN(WrenchMenuBadgeController);
+};
+
+#endif  // CHROME_BROWSER_UI_TOOLBAR_WRENCH_MENU_BADGE_CONTROLLER_H_