[Extensions] Observe unloading extensions in the TabHelper

chrome/browser/extensions/tab_helper.h

 // Copyright (c) 2012 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_TAB_HELPER_H_
 #define CHROME_BROWSER_EXTENSIONS_TAB_HELPER_H_
 
 #include <memory>
 #include <set>
 #include <string>
 
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
 #include "base/observer_list.h"
+#include "base/scoped_observer.h"
 #include "chrome/browser/extensions/active_tab_permission_granter.h"
 #include "chrome/browser/extensions/extension_reenabler.h"
 #include "chrome/common/extensions/webstore_install_result.h"
 #include "chrome/common/web_application_info.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
 #include "content/public/browser/web_contents_observer.h"
 #include "content/public/browser/web_contents_user_data.h"
 #include "extensions/browser/extension_function_dispatcher.h"
+#include "extensions/browser/extension_registry_observer.h"
 #include "extensions/browser/script_execution_observer.h"
 #include "extensions/browser/script_executor.h"
 #include "extensions/common/stack_frame.h"
 #include "third_party/skia/include/core/SkBitmap.h"
 
 class FaviconDownloader;
 
 namespace content {
 struct LoadCommittedDetails;
 class RenderFrameHost;
 }
 
 namespace gfx {
 class Image;
 }
 
 namespace extensions {
 class ExtensionActionRunner;
 class BookmarkAppHelper;
 class Extension;
 class LocationBarController;
 class WebstoreInlineInstallerFactory;
 
 // Per-tab extension helper. Also handles non-extension apps.
 class TabHelper : public content::WebContentsObserver,
-                  public extensions::ExtensionFunctionDispatcher::Delegate,
+                  public ExtensionFunctionDispatcher::Delegate,
+                  public ExtensionRegistryObserver,
                   public base::SupportsWeakPtr<TabHelper>,
                   public content::NotificationObserver,
                   public content::WebContentsUserData<TabHelper> {
  public:
   ~TabHelper() override;
 
   void CreateApplicationShortcuts();
   void CreateHostedAppFromWebContents();
   bool CanCreateApplicationShortcuts() const;
   bool CanCreateBookmarkApp() const;
@@ skipping 92 matching lines @@
   bool OnMessageReceived(const IPC::Message& message,
                          content::RenderFrameHost* render_frame_host) override;
   void DidCloneToNewWebContents(
       content::WebContents* old_web_contents,
       content::WebContents* new_web_contents) override;
 
   // extensions::ExtensionFunctionDispatcher::Delegate overrides.
   extensions::WindowController* GetExtensionWindowController() const override;
   content::WebContents* GetAssociatedWebContents() const override;
 
+  // ExtensionRegistryObserver:
+  void OnExtensionUnloaded(content::BrowserContext* browser_context,
+                           const Extension* extension,
+                           UnloadedExtensionInfo::Reason reason) override;
+
   // Message handlers.
   void OnDidGetWebApplicationInfo(const WebApplicationInfo& info);
   void OnInlineWebstoreInstall(content::RenderFrameHost* host,
                                int install_id,
                                int return_route_id,
                                const std::string& webstore_item_id,
                                const GURL& requestor_url,
                                int listeners_mask);
   void OnGetAppInstallState(content::RenderFrameHost* host,
                             const GURL& requestor_url,
@@ skipping 79 matching lines @@
 
   std::unique_ptr<BookmarkAppHelper> bookmark_app_helper_;
 
   // Creates WebstoreInlineInstaller instances for inline install triggers.
   std::unique_ptr<WebstoreInlineInstallerFactory>
       webstore_inline_installer_factory_;
 
   // The reenable prompt for disabled extensions, if any.
   std::unique_ptr<ExtensionReenabler> extension_reenabler_;
 
+  ScopedObserver<ExtensionRegistry, ExtensionRegistryObserver>
+      registry_observer_;
+
   // Vend weak pointers that can be invalidated to stop in-progress loads.
   base::WeakPtrFactory<TabHelper> image_loader_ptr_factory_;
 
   // Generic weak ptr factory for posting callbacks.
   base::WeakPtrFactory<TabHelper> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(TabHelper);
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_TAB_HELPER_H_