[iOS] Use TabHelperDelegateInstaller for AppLauncherBrowserAgent.

Bug: none
Change-Id: Icc5945a0defa2e488275fa2e396c8e6c616b4a14
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2145956
Commit-Queue: Kurt Horimoto <kkhorimoto@chromium.org>
Reviewed-by: Mark Cogan <marq@chromium.org>
Cr-Commit-Position: refs/heads/master@{#759419}

ios/chrome/browser/app_launcher/BUILD.gn

@@ -28,6 +28,7 @@ source_set("app_launcher") {
     "//ios/chrome/browser/overlays",
     "//ios/chrome/browser/overlays/public/web_content_area",
     "//ios/chrome/browser/reading_list",
+    "//ios/chrome/browser/tabs",
     "//ios/chrome/browser/u2f",
     "//ios/chrome/browser/web_state_list",
     "//ios/public/provider/chrome/browser",

ios/chrome/browser/app_launcher/app_launcher_browser_agent.h

@@ -6,10 +6,10 @@
 #define IOS_CHROME_BROWSER_APP_LAUNCHER_APP_LAUNCHER_BROWSER_AGENT_H_
 
 #include "base/scoped_observer.h"
+#import "ios/chrome/browser/app_launcher/app_launcher_tab_helper.h"
 #import "ios/chrome/browser/app_launcher/app_launcher_tab_helper_delegate.h"
-#import "ios/chrome/browser/main/browser_observer.h"
 #import "ios/chrome/browser/main/browser_user_data.h"
-#import "ios/chrome/browser/web_state_list/web_state_list_observer.h"
+#import "ios/chrome/browser/tabs/tab_helper_delegate_installer.h"
 
 class OverlayRequestQueue;
 
@@ -49,57 +49,11 @@ class AppLauncherBrowserAgent
     WebStateList* web_state_list_ = nullptr;
   };
 
-  // Helper object that sets up the delegates for all AppLauncherTabHelpers in
-  // the Browser's WebStateList.
-  class TabHelperDelegateInstaller : public WebStateListObserver {
-   public:
-    TabHelperDelegateInstaller(AppLauncherTabHelperDelegate* delegate,
-                               WebStateList* web_state_list);
-    ~TabHelperDelegateInstaller() override;
-
-   private:
-    // WebStateListObserver:
-    void WebStateInsertedAt(WebStateList* web_state_list,
-                            web::WebState* web_state,
-                            int index,
-                            bool activating) override;
-    void WebStateReplacedAt(WebStateList* web_state_list,
-                            web::WebState* old_web_state,
-                            web::WebState* new_web_state,
-                            int index) override;
-    void WillDetachWebStateAt(WebStateList* web_state_list,
-                              web::WebState* web_state,
-                              int index) override;
-
-    // The delegate that is installed for each WebState in the WebStateList.
-    AppLauncherTabHelperDelegate* delegate_ = nullptr;
-  };
-
-  // Helper object that unhooks the delegate installer when the Browser is
-  // destroyed.
-  class BrowserShutdownHelper : public BrowserObserver {
-   public:
-    BrowserShutdownHelper(Browser* browser,
-                          WebStateListObserver* web_state_list_observer);
-    ~BrowserShutdownHelper() override;
-
-   private:
-    // BrowserObserver:
-    void BrowserDestroyed(Browser* browser) override;
-
-    // The WebStateListObserver to detach upon destruction.
-    WebStateListObserver* web_state_list_observer_ = nullptr;
-    // Scoped observer for the Browser.
-    ScopedObserver<Browser, BrowserObserver> scoped_observer_{this};
-  };
-
   // Handler for app launches in the Browser.
   TabHelperDelegate tab_helper_delegate_;
-  // Installer for tab helper delegates.
-  TabHelperDelegateInstaller tab_helper_delegate_installer_;
-  // Helper object for cleaning up the BrowserAgent when the Browser is
-  // destroyed.
-  BrowserShutdownHelper shutdown_helper_;
+  // The tab helper delegate installer.
+  TabHelperDelegateInstaller<AppLauncherTabHelper, AppLauncherTabHelperDelegate>
+      tab_helper_delegate_installer_;
   // BrowserUserData key.
   BROWSER_USER_DATA_KEY_DECL();
 };

ios/chrome/browser/app_launcher/app_launcher_browser_agent.mm

@@ -74,9 +74,7 @@ void LaunchExternalApp(const GURL url, bool user_accepted = true) {
 
 AppLauncherBrowserAgent::AppLauncherBrowserAgent(Browser* browser)
     : tab_helper_delegate_(browser->GetWebStateList()),
-      tab_helper_delegate_installer_(&tab_helper_delegate_,
-                                     browser->GetWebStateList()),
-      shutdown_helper_(browser, &tab_helper_delegate_installer_) {}
+      tab_helper_delegate_installer_(&tab_helper_delegate_, browser) {}
 
 AppLauncherBrowserAgent::~AppLauncherBrowserAgent() = default;
 
@@ -159,72 +157,3 @@ AppLauncherBrowserAgent::TabHelperDelegate::GetQueueForAppLaunchDialog(
   return OverlayRequestQueue::FromWebState(queue_web_state,
                                            OverlayModality::kWebContentArea);
 }
-
-#pragma mark - AppLauncherBrowserAgent::TabHelperDelegateInstaller
-
-AppLauncherBrowserAgent::TabHelperDelegateInstaller::TabHelperDelegateInstaller(
-    AppLauncherTabHelperDelegate* delegate,
-    WebStateList* web_state_list)
-    : delegate_(delegate) {
-  DCHECK(delegate_);
-  DCHECK(web_state_list);
-  for (int i = 0; i < web_state_list->count(); ++i) {
-    AppLauncherTabHelper::FromWebState(web_state_list->GetWebStateAt(i))
-        ->SetDelegate(delegate_);
-  }
-}
-
-AppLauncherBrowserAgent::TabHelperDelegateInstaller::
-    ~TabHelperDelegateInstaller() = default;
-
-#pragma mark WebStateListObserver
-
-void AppLauncherBrowserAgent::TabHelperDelegateInstaller::WebStateInsertedAt(
-    WebStateList* web_state_list,
-    web::WebState* web_state,
-    int index,
-    bool activating) {
-  AppLauncherTabHelper::FromWebState(web_state)->SetDelegate(delegate_);
-}
-
-void AppLauncherBrowserAgent::TabHelperDelegateInstaller::WebStateReplacedAt(
-    WebStateList* web_state_list,
-    web::WebState* old_web_state,
-    web::WebState* new_web_state,
-    int index) {
-  AppLauncherTabHelper::FromWebState(old_web_state)->SetDelegate(nullptr);
-  AppLauncherTabHelper::FromWebState(new_web_state)->SetDelegate(delegate_);
-}
-
-void AppLauncherBrowserAgent::TabHelperDelegateInstaller::WillDetachWebStateAt(
-    WebStateList* web_state_list,
-    web::WebState* web_state,
-    int index) {
-  AppLauncherTabHelper::FromWebState(web_state)->SetDelegate(nullptr);
-}
-
-#pragma mark - AppLauncherBrowserAgent::BrowserShutdownHelper
-
-AppLauncherBrowserAgent::BrowserShutdownHelper::BrowserShutdownHelper(
-    Browser* browser,
-    WebStateListObserver* web_state_list_observer)
-    : web_state_list_observer_(web_state_list_observer) {
-  DCHECK(browser);
-  DCHECK(web_state_list_observer_);
-  scoped_observer_.Add(browser);
-  browser->GetWebStateList()->AddObserver(web_state_list_observer_);
-}
-
-AppLauncherBrowserAgent::BrowserShutdownHelper::~BrowserShutdownHelper() {
-  // The WebStateListObserver must be detached before destruction.
-  DCHECK(!web_state_list_observer_);
-}
-
-#pragma mark BrowserObserver
-
-void AppLauncherBrowserAgent::BrowserShutdownHelper::BrowserDestroyed(
-    Browser* browser) {
-  scoped_observer_.Remove(browser);
-  browser->GetWebStateList()->RemoveObserver(web_state_list_observer_);
-  web_state_list_observer_ = nullptr;
-}