Replace TabModel with WebStateList in GoogleLandingController.

ios/chrome/browser/ui/ntp/google_landing_mediator.mm

 // Copyright 2017 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.
 
 #import "ios/chrome/browser/ui/ntp/google_landing_mediator.h"
 
 #import "base/ios/weak_nsobject.h"
 #include "base/mac/scoped_nsobject.h"
 #include "base/metrics/user_metrics.h"
 #include "base/metrics/user_metrics_action.h"
@@ skipping 13 matching lines @@
 #import "ios/chrome/browser/ntp_tiles/most_visited_sites_observer_bridge.h"
 #include "ios/chrome/browser/reading_list/reading_list_model_factory.h"
 #include "ios/chrome/browser/search_engines/template_url_service_factory.h"
 #import "ios/chrome/browser/ui/browser_view_controller.h"
 #import "ios/chrome/browser/ui/commands/UIKit+ChromeExecuteCommand.h"
 #import "ios/chrome/browser/ui/commands/generic_chrome_command.h"
 #import "ios/chrome/browser/ui/ntp/google_landing_consumer.h"
 #import "ios/chrome/browser/ui/ntp/notification_promo_whats_new.h"
 #import "ios/chrome/browser/ui/toolbar/web_toolbar_controller.h"
 #import "ios/chrome/browser/ui/url_loader.h"
+#import "ios/chrome/browser/web_state_list/web_state_list.h"
+#import "ios/chrome/browser/web_state_list/web_state_list_observer_bridge.h"
 #include "ios/public/provider/chrome/browser/chrome_browser_provider.h"
 #include "ios/public/provider/chrome/browser/voice/voice_search_provider.h"
 
 using base::UserMetricsAction;
 
 namespace {
 
 const NSInteger kMaxNumMostVisitedFavicons = 8;
 
 }  // namespace
@@ skipping 28 matching lines @@
 SearchEngineObserver::~SearchEngineObserver() {
   _templateURLService->RemoveObserver(this);
 }
 
 void SearchEngineObserver::OnTemplateURLServiceChanged() {
   [_owner updateShowLogo];
 }
 
 }  // namespace google_landing
 
-@interface GoogleLandingMediator ()<MostVisitedSitesObserving> {
+@interface GoogleLandingMediator ()<MostVisitedSitesObserving,
+                                    WebStateListObserving> {
   // The ChromeBrowserState associated with this mediator.
   ios::ChromeBrowserState* _browserState;  // Weak.
 
   // |YES| if impressions were logged already and shouldn't be logged again.
   BOOL _recordedPageImpression;
 
   // The designated url loader.
   id<UrlLoader> _loader;  // Weak.
 
   // Delegate to focus and blur the omnibox.
@@ skipping 12 matching lines @@
       _most_visited_observer_bridge;
 
   std::unique_ptr<ntp_tiles::MostVisitedSites> _most_visited_sites;
 
   // Most visited data from the MostVisitedSites service (copied upon receiving
   // the callback).
   ntp_tiles::NTPTilesVector _mostVisitedData;
 
   base::WeakNSProtocol<id<WebToolbarDelegate>> _webToolbarDelegate;
 
-  base::scoped_nsobject<TabModel> _tabModel;
+  // Observes the WebStateList so that this mediator can update the UI when the
+  // active WebState changes.
+  std::unique_ptr<WebStateListObserverBridge> _webStateListObserver;
 
   // What's new promo.
   std::unique_ptr<NotificationPromoWhatsNew> _notification_promo;
 }
 
 // Consumer to handle google landing update notifications.
 @property(nonatomic) id<GoogleLandingConsumer> consumer;
 
+// The WebStateList that is being observed by this mediator.
+@property(nonatomic, assign) WebStateList* webStateList;
+
 // Perform initial setup.
 - (void)setUp;
 
 @end
 
 @implementation GoogleLandingMediator
 
 @synthesize consumer = _consumer;
+@synthesize webStateList = _webStateList;
 
 - (instancetype)initWithConsumer:(id<GoogleLandingConsumer>)consumer
                     browserState:(ios::ChromeBrowserState*)browserState
                           loader:(id<UrlLoader>)loader
                          focuser:(id<OmniboxFocuser>)focuser
               webToolbarDelegate:(id<WebToolbarDelegate>)webToolbarDelegate
-                        tabModel:(TabModel*)tabModel {
+                    webStateList:(WebStateList*)webStateList {
   self = [super init];
   if (self) {
     self.consumer = consumer;
     _browserState = browserState;
     _loader = loader;
     _focuser.reset(focuser);
     _webToolbarDelegate.reset(webToolbarDelegate);
-    _tabModel.reset([tabModel retain]);
+    _webStateList = webStateList;
+
+    _webStateListObserver = base::MakeUnique<WebStateListObserverBridge>(self);

[rohitrao (ping after 24h), 2017/04/19 19:26:33]

Louis has an example CL that uses a ScopedObserver, if you want to look at that
and see if you like it.

[justincohen, 2017/04/19 21:12:23]

Acknowledged.

+    _webStateList->AddObserver(_webStateListObserver.get());
+
     [self setUp];
   }
   return self;
 }
 
 - (void)dealloc {
+  _webStateList->RemoveObserver(_webStateListObserver.get());

[rohitrao (ping after 24h), 2017/04/19 19:26:33]

dealloc might be too late, if this object has its lifetime artificially extended
by a block.  We're working on developing a consistent pattern to use here.

[justincohen, 2017/04/19 21:12:23]

I think the view's life can be extended, but not the controller?  

   [[NSNotificationCenter defaultCenter] removeObserver:self.consumer];
   [super dealloc];
 }
 
 - (void)setUp {
   self.consumer.offTheRecord = _browserState->IsOffTheRecord();
   self.consumer.voiceSearchEnabled = ios::GetChromeBrowserProvider()
                                          ->GetVoiceSearchProvider()
                                          ->IsVoiceSearchEnabled();
+  self.consumer.tabCount = self.webStateList->count();
 
   // Set up template URL service to listen for default search engine changes.
   _templateURLService =
       ios::TemplateURLServiceFactory::GetForBrowserState(_browserState);
   _observer.reset(
       new google_landing::SearchEngineObserver(self, _templateURLService));
   _templateURLService->Load();
   _doodleController.reset(ios::GetChromeBrowserProvider()->CreateLogoVendor(
       _browserState, _loader));
   self.consumer.logoVendor = _doodleController;
@@ skipping 65 matching lines @@
 - (void)onIconMadeAvailable:(const GURL&)siteUrl {
   for (size_t i = 0; i < _mostVisitedData.size(); ++i) {
     const ntp_tiles::NTPTile& ntpTile = _mostVisitedData[i];
     if (ntpTile.url == siteUrl) {
       [self.consumer mostVisitedIconMadeAvailableAtIndex:i];
       break;
     }
   }
 }
 
+#pragma mark - WebStateListObserving
+
+- (void)webStateList:(WebStateList*)webStateList
+    didInsertWebState:(web::WebState*)webState
+              atIndex:(int)index {
+  self.consumer.tabCount = self.webStateList->count();
+}
+
+- (void)webStateList:(WebStateList*)webStateList
+    didDetachWebState:(web::WebState*)webState
+              atIndex:(int)atIndex {
+  self.consumer.tabCount = self.webStateList->count();
+}
+
 #pragma mark - GoogleLandingDataSource
 
 - (NSUInteger)maxSitesShown {
   return kMaxNumMostVisitedFavicons;
 }
 
 - (void)addBlacklistedURL:(const GURL&)url {
   _most_visited_sites->AddOrRemoveBlacklistedUrl(url, true);
 }
 
@@ skipping 27 matching lines @@
 }
 
 - (favicon::LargeIconService*)largeIconService {
   return IOSChromeLargeIconServiceFactory::GetForBrowserState(_browserState);
 }
 
 - (id<WebToolbarDelegate>)toolbarDelegate {
   return _webToolbarDelegate;
 }
 
-- (TabModel*)tabModel {
-  return _tabModel;
-}
-
 - (BOOL)promoCanShow {
   return _notification_promo && _notification_promo->CanShow();
 }
 
 - (NSString*)promoText {
   DCHECK(_notification_promo);
   return base::SysUTF8ToNSString(_notification_promo->promo_text());
 }
 
 - (WhatsNewIcon)promoIcon {
@@ skipping 87 matching lines @@
 
 - (void)onFakeboxBlur {
   [_focuser onFakeboxBlur];
 }
 
 - (void)onFakeboxAnimationComplete {
   [_focuser onFakeboxAnimationComplete];
 }
 
 @end