[Media Router] Unload the legacy Cast extension at install

chrome/browser/ui/toolbar/component_toolbar_actions_factory.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_COMPONENT_TOOLBAR_ACTIONS_FACTORY_H_
 #define CHROME_BROWSER_UI_TOOLBAR_COMPONENT_TOOLBAR_ACTIONS_FACTORY_H_
 
 #include <memory>
 #include <set>
 #include <string>
 
 #include "base/macros.h"
+#include "base/scoped_observer.h"
+#include "extensions/browser/extension_registry_observer.h"
 
 class Browser;
-class ExtensionService;
 class Profile;
 class ToolbarActionsBar;
 class ToolbarActionViewController;
 
 namespace extensions {
 class ExtensionRegistry;
-}
+class ExtensionSystem;
+}  // namespace extensions
 
 // The registry for all component toolbar actions. Component toolbar actions
 // are actions that live in the toolbar (like extension actions), but are for
 // components of Chrome, such as Media Router.
-class ComponentToolbarActionsFactory {
+class ComponentToolbarActionsFactory
+    : public extensions::ExtensionRegistryObserver {
  public:
   // Extension and component action IDs.
   static const char kCastBetaExtensionId[];
   static const char kCastExtensionId[];
   static const char kMediaRouterActionId[];
 
   explicit ComponentToolbarActionsFactory(Profile* profile);
-  virtual ~ComponentToolbarActionsFactory();
+  ~ComponentToolbarActionsFactory() override;
 
   // Returns a set of IDs of the component actions that should be present when
   // the toolbar model is initialized.
   virtual std::set<std::string> GetInitialComponentIds();
 
   // Called when component actions are added or removed before the toolbar model
   // is initialized. Adds or removes |action_id| to/from |initial_ids_| as
   // necessary.
   void OnAddComponentActionBeforeInit(const std::string& action_id);
   void OnRemoveComponentActionBeforeInit(const std::string& action_id);
 
   // Returns the controller responsible for the component action associated with
   // |action_id| in |bar|. Declared virtual for testing.
   virtual std::unique_ptr<ToolbarActionViewController>
   GetComponentToolbarActionForId(const std::string& action_id,
                                  Browser* browser,
                                  ToolbarActionsBar* bar);
 
   // Unloads extensions that were migrated to component actions and therefore
   // are no longer needed.
-  void UnloadMigratedExtensions(ExtensionService* service,
-                                extensions::ExtensionRegistry* registry);
+  void UnloadMigratedExtensions();
+
+  // extensions::ExtensionRegistryObserver:
+  void OnExtensionInstalled(content::BrowserContext* browser_context,
+                            const extensions::Extension* extension,
+                            bool is_update) override;
 
  private:
-  // Unloads an extension if it is active.
-  void UnloadExtension(ExtensionService* service,
-                       extensions::ExtensionRegistry* registry,
-                       const std::string& extension_id);
+  // Unloads an extension if it is installed.
+  void UnloadExtension(const std::string& extension_id);
 
-  Profile* profile_;
+  Profile* const profile_;
 
   // IDs of component actions that should be added to the toolbar model when it
   // gets initialized.
   std::set<std::string> initial_ids_;
 
+  // The ExtensionRegistry and ExtensionSystem for the profile, used for
+  // detecting and unloading migrated extensions.
+  extensions::ExtensionRegistry* const extension_registry_;
+  extensions::ExtensionSystem* const extension_system_;
+
+  ScopedObserver<extensions::ExtensionRegistry, ExtensionRegistryObserver>
+      extension_registry_observer_;
+
   DISALLOW_COPY_AND_ASSIGN(ComponentToolbarActionsFactory);
 };
 
 #endif  // CHROME_BROWSER_UI_TOOLBAR_COMPONENT_TOOLBAR_ACTIONS_FACTORY_H_