[ios] Convert BlockedPopupHandler into a tab helper class.

ios/chrome/browser/tabs/tab.mm

Index: ios/chrome/browser/tabs/tab.mm
diff --git a/ios/chrome/browser/tabs/tab.mm b/ios/chrome/browser/tabs/tab.mm
index db9e457ccfcf1faff648d8faf70497230d8c6cbd..75c2cc7af1659787fa12a81c2db9aead76c80016 100644
--- a/ios/chrome/browser/tabs/tab.mm
+++ b/ios/chrome/browser/tabs/tab.mm
@@ -115,7 +115,7 @@
 #include "ios/chrome/browser/ui/ui_util.h"
 #import "ios/chrome/browser/ui/util/top_view_controller.h"
 #import "ios/chrome/browser/web/auto_reload_bridge.h"
-#import "ios/chrome/browser/web/blocked_popup_handler.h"
+#import "ios/chrome/browser/web/blocked_popup_tab_helper.h"
 #import "ios/chrome/browser/web/external_app_launcher.h"
 #include "ios/chrome/browser/web/network_activity_indicator_tab_helper.h"
 #import "ios/chrome/browser/web/passkit_dialog_provider.h"
@@ -200,8 +200,7 @@ enum class RendererTerminationTabState {
 };
 }  // namespace
 
-@interface Tab ()<BlockedPopupHandlerDelegate,
-                  CRWWebStateObserver,
+@interface Tab ()<CRWWebStateObserver,
                   CRWWebUserInterfaceDelegate,
                   FindInPageControllerDelegate,
                   ReaderModeControllerDelegate> {
@@ -279,9 +278,6 @@ enum class RendererTerminationTabState {
   // Handles autofill.
   base::scoped_nsobject<AutofillController> autofillController_;
 
-  // The popup blocker to show blocked popup to the user.
-  std::unique_ptr<BlockedPopupHandler> popupHandler_;
-
   // Handles find on page.
   base::scoped_nsobject<FindInPageController> findInPageController_;
 
@@ -361,9 +357,6 @@ enum class RendererTerminationTabState {
 // Saves the current title to the history database.
 - (void)saveTitleToHistoryDB;
 
-// Returns a lazily instantiated popup handler.
-- (BlockedPopupHandler*)popupHandler;
-
 // Adds the current session entry to this history database.
 - (void)addCurrentEntryToHistoryDB;
 
@@ -570,6 +563,7 @@ void TabInfoBarObserver::OnInfoBarReplaced(infobars::InfoBar* old_infobar,
     IOSChromeSyncedTabDelegate::CreateForWebState(self.webState);
     InfoBarManagerImpl::CreateForWebState(self.webState);
     IOSSecurityStateTabHelper::CreateForWebState(self.webState);
+    BlockedPopupTabHelper::CreateForWebState(self.webState);
 
     if (reading_list::switches::IsReadingListEnabled()) {
       ReadingListModel* model =
@@ -1640,14 +1634,6 @@ void TabInfoBarObserver::OnInfoBarReplaced(infobars::InfoBar* old_infobar,
   snapshotOverlayProvider_.reset(snapshotOverlayProvider);
 }
 
-- (BlockedPopupHandler*)popupHandler {
-  if (!popupHandler_.get()) {
-    popupHandler_.reset(new BlockedPopupHandler(self.browserState));
-    popupHandler_->SetDelegate(self);
-  }
-  return popupHandler_.get();
-}
-
 - (void)evaluateU2FResultFromURL:(const GURL&)URL {
   DCHECK(U2FController_);
   [U2FController_ evaluateU2FResultFromU2FURL:URL webState:self.webState];
@@ -2115,7 +2101,8 @@ void TabInfoBarObserver::OnInfoBarReplaced(infobars::InfoBar* old_infobar,
 
 - (void)webController:(CRWWebController*)webController
         didBlockPopup:(const web::BlockedPopupInfo&)blockedPopupInfo {
-  [self popupHandler]->HandlePopup(blockedPopupInfo);
+  BlockedPopupTabHelper::FromWebState(self.webState)
+      ->HandlePopup(blockedPopupInfo);
 }
 
 - (CGFloat)headerHeightForWebController:(CRWWebController*)webController {