ARC: Add badge for Chrome hosted Apps if Arc++ is enabled.

chrome/browser/ui/ash/launcher/launcher_app_updater.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 CHROME_BROWSER_UI_ASH_LAUNCHER_LAUNCHER_APP_UPDATER_H_
 #define CHROME_BROWSER_UI_ASH_LAUNCHER_LAUNCHER_APP_UPDATER_H_
 
 #include <string>
 
 #include "base/macros.h"
 
 namespace content {
 class BrowserContext;
 }
 
 // Responsible for handling of Chrome app life-cycle events.
 class LauncherAppUpdater {
  public:
   class Delegate {
    public:
     virtual void OnAppInstalled(content::BrowserContext* browser_context,
-                                const std::string& app_id) = 0;
+                                const std::string& app_id) {}
     virtual void OnAppUpdated(content::BrowserContext* browser_context,
-                              const std::string& app_id) = 0;
+                              const std::string& app_id) {}
+    virtual void OnAppUninstalledPrepared(
+        content::BrowserContext* browser_context,
+        const std::string& app_id) {}
     virtual void OnAppUninstalled(content::BrowserContext* browser_context,
-                                  const std::string& app_id) = 0;
+                                  const std::string& app_id) {}
 
    protected:
     virtual ~Delegate() {}
   };
 
   virtual ~LauncherAppUpdater();
 
   Delegate* delegate() { return delegate_; }
 
   content::BrowserContext* browser_context() { return browser_context_; }
 
  protected:
   LauncherAppUpdater(Delegate* delegate,
                      content::BrowserContext* browser_context);
 
  private:
   // Unowned pointers
   Delegate* delegate_;
   content::BrowserContext* browser_context_;
 
   DISALLOW_COPY_AND_ASSIGN(LauncherAppUpdater);
 };
 
 #endif  // CHROME_BROWSER_UI_ASH_LAUNCHER_LAUNCHER_APP_UPDATER_H_