[ObjC ARC] Converts ios/chrome/browser/ui/tab_switcher:tab_switcher to ARC.

ios/chrome/browser/ui/tab_switcher/tab_switcher_model.mm

 // Copyright 2015 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/tab_switcher/tab_switcher_model.h"
 
 #include <memory>
 
 #include "base/memory/ptr_util.h"
 #include "components/browser_sync/profile_sync_service.h"
 #include "components/sessions/core/session_id.h"
 #include "components/signin/core/browser/signin_manager.h"
 #include "ios/chrome/browser/browser_state/chrome_browser_state.h"
 #include "ios/chrome/browser/signin/signin_manager_factory.h"
 #include "ios/chrome/browser/sync/ios_chrome_profile_sync_service_factory.h"
 #include "ios/chrome/browser/sync/sync_setup_service.h"
 #include "ios/chrome/browser/sync/sync_setup_service_factory.h"
 #import "ios/chrome/browser/tabs/tab.h"
 #import "ios/chrome/browser/tabs/tab_model.h"
 #include "ios/chrome/browser/ui/ntp/recent_tabs/synced_sessions.h"
 #import "ios/chrome/browser/ui/tab_switcher/tab_model_snapshot.h"
 #import "ios/chrome/browser/ui/tab_switcher/tab_switcher_cache.h"
 #import "ios/chrome/browser/ui/tab_switcher/tab_switcher_model_private.h"
 #import "ios/chrome/browser/ui/tab_switcher/tab_switcher_panel_cell.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 bool TabSwitcherSessionTypeIsLocalSession(TabSwitcherSessionType sessionType) {
   return sessionType == TabSwitcherSessionType::OFF_THE_RECORD_SESSION ||
          sessionType == TabSwitcherSessionType::REGULAR_SESSION;
 }
 
 namespace {
 
 class TagAndIndex {
  public:
   TagAndIndex(std::string const& tag, size_t index)
@@ skipping 11 matching lines @@
     set->insert(TagAndIndex(sessions.GetSession(i)->tag, i));
   }
 }
 
 }  // namespace
 
 @interface TabSwitcherModel () {
   // The browser state.
   ios::ChromeBrowserState* _browserState;  // weak
   // The tab models.
-  TabModel* _mainTabModel;  // weak
-  TabModel* _otrTabModel;   // weak
+  __weak TabModel* _mainTabModel;
+  __weak TabModel* _otrTabModel;
   // The delegate for event callbacks.
-  id<TabSwitcherModelDelegate> _delegate;  // weak, owns us.
+  __weak id<TabSwitcherModelDelegate> _delegate;
   // The synced sessions. Must never be null.
   std::unique_ptr<synced_sessions::SyncedSessions> _syncedSessions;
   // The synced sessions change observer.
   std::unique_ptr<synced_sessions::SyncedSessionsObserverBridge>
       _syncedSessionsObserver;
   // Snapshots of the |_mainTabModel| and |_otrTabModel|.
   std::unique_ptr<TabModelSnapshot> _mainTabModelSnapshot;
   std::unique_ptr<TabModelSnapshot> _otrTabModelSnapshot;
   // The cache holding resized tabs snapshots.
-  base::scoped_nsobject<TabSwitcherCache> _cache;
+  TabSwitcherCache* _cache;
 }
 
 // Returns the type of the local session corresponding to the given |tabModel|.
 // |tabModel| MUST be equal to either |_mainTabModel|, or |_otrTabModel|.
 - (TabSwitcherSessionType)typeOfLocalSessionForTabModel:(TabModel*)tabModel;
 @end
 
 @implementation TabSwitcherModel
 
 @synthesize mainTabModel = _mainTabModel;
@@ skipping 13 matching lines @@
     _delegate = delegate;
     _syncedSessions.reset(new synced_sessions::SyncedSessions());
     _syncedSessionsObserver.reset(
         new synced_sessions::SyncedSessionsObserverBridge(self, _browserState));
     _mainTabModel = mainTabModel;
     _otrTabModel = otrTabModel;
     _mainTabModelSnapshot.reset(new TabModelSnapshot(mainTabModel));
     _otrTabModelSnapshot.reset(new TabModelSnapshot(otrTabModel));
     [_mainTabModel addObserver:self];
     [_otrTabModel addObserver:self];
-    _cache.reset([cache retain]);
+    _cache = cache;
   }
   return self;
 }
 
 - (void)setMainTabModel:(TabModel*)mainTabModel
             otrTabModel:(TabModel*)otrTabModel {
-  [self replaceOldTabModel:&_mainTabModel withTabModel:mainTabModel];
-  [self replaceOldTabModel:&_otrTabModel withTabModel:otrTabModel];
+  [self replaceMainTabModelWithTabModel:mainTabModel];
+  [self replaceOTRTabModelWithTabModel:otrTabModel];
 }
 
-- (void)replaceOldTabModel:(TabModel**)oldTabModel
-              withTabModel:(TabModel*)newTabModel {
-  if (*oldTabModel == newTabModel)
+- (void)replaceMainTabModelWithTabModel:(TabModel*)newTabModel {
+  if (_mainTabModel == newTabModel)
     return;
-  [*oldTabModel removeObserver:self];
-  *oldTabModel = newTabModel;
+  [_mainTabModel removeObserver:self];
+  _mainTabModel = newTabModel;
   [newTabModel addObserver:self];
   // Calling |tabModelChanged:| may trigger an animated refresh of the
   // Tab Switcher's collection view.
+  // Here in |replaceOldTabModel:withTabModel:| the animation is undesirable.
+  [UIView performWithoutAnimation:^{
+    [self tabModelChanged:newTabModel];
+  }];
+}
+
+- (void)replaceOTRTabModelWithTabModel:(TabModel*)newTabModel {
+  if (_otrTabModel == newTabModel)
+    return;
+  [_otrTabModel removeObserver:self];
+  _otrTabModel = newTabModel;
+  [newTabModel addObserver:self];
+  // Calling |tabModelChanged:| may trigger an animated refresh of the
+  // Tab Switcher's collection view.
   // Here in |replaceOldTabModel:withTabModel:| the animation is undesirable.
   [UIView performWithoutAnimation:^{
     [self tabModelChanged:newTabModel];
   }];
 }
 
 - (void)dealloc {
   [_mainTabModel removeObserver:self];
   [_otrTabModel removeObserver:self];
-  [super dealloc];
 }
 
 - (NSInteger)sessionCount {
   const NSInteger mainTabModelSessionCount = 1;
   const NSInteger otrTabModelSessionCount = 1;
   return mainTabModelSessionCount + otrTabModelSessionCount +
          [self distantSessionCount];
 }
 
 - (NSInteger)distantSessionCount {
@@ skipping 250 matching lines @@
   [self tabModelChanged:model];
 }
 
 - (void)tabModel:(TabModel*)model
     didChangeTabSnapshot:(Tab*)tab
                withImage:(UIImage*)image {
   [self tabModelChanged:model];
 }
 
 @end