[ios] ARCMigrate ios/chrome/browser/tabs/tab_model.mm to ARC.

ios/chrome/browser/tabs/tab_model.mm

 // Copyright 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.
 
 #import "ios/chrome/browser/tabs/tab_model.h"
 
 #include <cstdint>
 #include <utility>
 #include <vector>
 
 #include "base/bind.h"
 #include "base/logging.h"
 #import "base/mac/foundation_util.h"
-#import "base/mac/scoped_nsobject.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/metrics/user_metrics_action.h"
 #include "base/strings/sys_string_conversions.h"
 #include "base/task/cancelable_task_tracker.h"
 #include "components/sessions/core/serialized_navigation_entry.h"
 #include "components/sessions/core/session_id.h"
 #include "components/sessions/core/tab_restore_service.h"
 #include "components/sessions/ios/ios_live_tab.h"
 #include "ios/chrome/browser/browser_state/chrome_browser_state.h"
 #include "ios/chrome/browser/chrome_url_constants.h"
@@ skipping 28 matching lines @@
 #include "ios/web/public/certificate_policy_cache.h"
 #include "ios/web/public/navigation_item.h"
 #import "ios/web/public/navigation_manager.h"
 #import "ios/web/public/serializable_user_data_manager.h"
 #include "ios/web/public/web_state/session_certificate_policy_cache.h"
 #include "ios/web/public/web_thread.h"
 #import "ios/web/web_state/ui/crw_web_controller.h"
 #import "ios/web/web_state/web_state_impl.h"
 #include "url/gurl.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 NSString* const kTabModelTabWillStartLoadingNotification =
     @"kTabModelTabWillStartLoadingNotification";
 NSString* const kTabModelTabDidStartLoadingNotification =
     @"kTabModelTabDidStartLoadingNotification";
 NSString* const kTabModelTabDidFinishLoadingNotification =
     @"kTabModelTabDidFinishLoadingNotification";
 NSString* const kTabModelAllTabsDidCloseNotification =
     @"kTabModelAllTabsDidCloseNotification";
 NSString* const kTabModelTabDeselectedNotification =
     @"kTabModelTabDeselectedNotification";
@@ skipping 67 matching lines @@
 
   // Helper providing NSFastEnumeration implementation over the WebStateList.
   std::unique_ptr<WebStateListFastEnumerationHelper> _fastEnumerationHelper;
 
   // WebStateListObservers reacting to modifications of the model (may send
   // notification, translate and forward events, update metrics, ...).
   std::vector<std::unique_ptr<WebStateListObserver>> _webStateListObservers;
 
   // Strong references to id<WebStateListObserving> wrapped by non-owning
   // WebStateListObserverBridges.
-  base::scoped_nsobject<NSArray<id<WebStateListObserving>>>
-      _retainedWebStateListObservers;
+  NSArray<id<WebStateListObserving>>* _retainedWebStateListObservers;
 
   // The delegate for sync.
   std::unique_ptr<TabModelSyncedWindowDelegate> _syncedWindowDelegate;
 
   // Counters for metrics.
   WebStateListMetricsObserver* _webStateListMetricsObserver;
 
   // Backs up property with the same name.
   std::unique_ptr<TabUsageRecorder> _tabUsageRecorder;
   // Backs up property with the same name.
   const SessionID _sessionID;
   // Saves session's state.
-  base::scoped_nsobject<SessionServiceIOS> _sessionService;
+  SessionServiceIOS* _sessionService;
   // List of TabModelObservers.
-  base::scoped_nsobject<TabModelObservers> _observers;
+  TabModelObservers* _observers;
 
   // Used to ensure thread-safety of the certificate policy management code.
   base::CancelableTaskTracker _clearPoliciesTaskTracker;
 }
 
 // Session window for the contents of the tab model.
 @property(nonatomic, readonly) SessionIOS* sessionForSaving;
 
 // Helper method that posts a notification with the given name with |tab|
 // in the userInfo dictionary under the kTabModelTabKey.
@@ skipping 36 matching lines @@
   // the WebStateList destructor is called.
   @autoreleasepool {
     [self closeAllTabs];
   }
 
   // Unregister all observers after closing all the tabs as some of them are
   // required to properly clean up the Tabs.
   for (const auto& webStateListObserver : _webStateListObservers)
     _webStateList->RemoveObserver(webStateListObserver.get());
   _webStateListObservers.clear();
-  _retainedWebStateListObservers.reset();
+  _retainedWebStateListObservers = nil;
 
   _clearPoliciesTaskTracker.TryCancelAll();
 

[stkhapugin, 2017/05/03 11:56:12]

nit: remove newline

[sdefresne, 2017/05/03 13:03:10]

Done.

-  [super dealloc];
 }
 
 #pragma mark - Public methods
 
 - (Tab*)currentTab {
   web::WebState* webState = _webStateList->GetActiveWebState();
   return webState ? LegacyTabHelper::GetTabForWebState(webState) : nil;
 }
 
 - (void)setCurrentTab:(Tab*)newTab {
@@ skipping 24 matching lines @@
 }
 
 - (WebStateList*)webStateList {
   return _webStateList.get();
 }
 
 - (instancetype)initWithSessionWindow:(SessionWindowIOS*)window
                        sessionService:(SessionServiceIOS*)service
                          browserState:(ios::ChromeBrowserState*)browserState {
   if ((self = [super init])) {
-    _observers.reset([[TabModelObservers observers] retain]);
+    _observers = [TabModelObservers observers];
 
     _webStateListDelegate =
         base::MakeUnique<TabModelWebStateListDelegate>(self);
     _webStateList = base::MakeUnique<WebStateList>(_webStateListDelegate.get());
 
     _fastEnumerationHelper =
         base::MakeUnique<WebStateListFastEnumerationHelper>(
             _webStateList.get(), [[TabModelWebStateProxyFactory alloc] init]);
 
     _browserState = browserState;
     DCHECK(_browserState);
 
     // Normal browser states are the only ones to get tab restore. Tab sync
     // handles incognito browser states by filtering on profile, so it's
     // important to the backend code to always have a sync window delegate.
     if (!_browserState->IsOffTheRecord()) {
       // Set up the usage recorder before tabs are created.
       _tabUsageRecorder = base::MakeUnique<TabUsageRecorder>(self);
     }
     _syncedWindowDelegate = base::MakeUnique<TabModelSyncedWindowDelegate>(
         _webStateList.get(), _sessionID);
 
     // There must be a valid session service defined to consume session windows.
     DCHECK(service);
-    _sessionService.reset([service retain]);
+    _sessionService = service;
 
-    base::scoped_nsobject<NSMutableArray<id<WebStateListObserving>>>
-        retainedWebStateListObservers([[NSMutableArray alloc] init]);
+    NSMutableArray<id<WebStateListObserving>>* retainedWebStateListObservers =
+        [[NSMutableArray alloc] init];
 
-    base::scoped_nsobject<TabModelClosingWebStateObserver>
-        tabModelClosingWebStateObserver([[TabModelClosingWebStateObserver alloc]
-            initWithTabModel:self
-              restoreService:IOSChromeTabRestoreServiceFactory::
-                                 GetForBrowserState(_browserState)]);
+    TabModelClosingWebStateObserver* tabModelClosingWebStateObserver = [
+        [TabModelClosingWebStateObserver alloc]
+        initWithTabModel:self
+          restoreService:IOSChromeTabRestoreServiceFactory::GetForBrowserState(
+                             _browserState)];
     [retainedWebStateListObservers addObject:tabModelClosingWebStateObserver];
 
     _webStateListObservers.push_back(
         base::MakeUnique<WebStateListObserverBridge>(
             tabModelClosingWebStateObserver));
 
     _webStateListObservers.push_back(
         base::MakeUnique<SnapshotCacheWebStateListObserver>(
             [SnapshotCache sharedInstance]));
     if (_tabUsageRecorder) {
       _webStateListObservers.push_back(
           base::MakeUnique<TabUsageRecorderWebStateListObserver>(
               _tabUsageRecorder.get()));
     }
     _webStateListObservers.push_back(base::MakeUnique<TabParentingObserver>());
 
-    base::scoped_nsobject<TabModelSelectedTabObserver>
-        tabModelSelectedTabObserver(
-            [[TabModelSelectedTabObserver alloc] initWithTabModel:self]);
+    TabModelSelectedTabObserver* tabModelSelectedTabObserver =
+        [[TabModelSelectedTabObserver alloc] initWithTabModel:self];
     [retainedWebStateListObservers addObject:tabModelSelectedTabObserver];
     _webStateListObservers.push_back(
         base::MakeUnique<WebStateListObserverBridge>(
             tabModelSelectedTabObserver));
 
-    base::scoped_nsobject<TabModelObserversBridge> tabModelObserversBridge(
+    TabModelObserversBridge* tabModelObserversBridge =
         [[TabModelObserversBridge alloc] initWithTabModel:self
-                                        tabModelObservers:_observers.get()]);
+                                        tabModelObservers:_observers];
     [retainedWebStateListObservers addObject:tabModelObserversBridge];
     _webStateListObservers.push_back(
         base::MakeUnique<WebStateListObserverBridge>(tabModelObserversBridge));
 
     auto webStateListMetricsObserver =
         base::MakeUnique<WebStateListMetricsObserver>();
     _webStateListMetricsObserver = webStateListMetricsObserver.get();
     _webStateListObservers.push_back(std::move(webStateListMetricsObserver));
 
     for (const auto& webStateListObserver : _webStateListObservers)
       _webStateList->AddObserver(webStateListObserver.get());
-    _retainedWebStateListObservers.reset([retainedWebStateListObservers copy]);
+    _retainedWebStateListObservers = [retainedWebStateListObservers copy];
 
     if (window) {
       DCHECK([_observers empty]);
       // Restore the session and reset the session metrics (as the event have
       // not been generated by the user but by a cold start cycle).
       [self restoreSessionWindow:window persistState:NO];
       [self resetSessionMetrics];
     }
 
     // Register for resign active notification.
@@ skipping 307 matching lines @@
     }
   }
 
   int tabCount = static_cast<int>(self.count);
   UMA_HISTOGRAM_CUSTOM_COUNTS("Tabs.TabCountPerLoad", tabCount, 1, 200, 50);
 }
 
 #pragma mark - NSFastEnumeration
 
 - (NSUInteger)countByEnumeratingWithState:(NSFastEnumerationState*)state
-                                  objects:(id*)objects
+                                  objects:(id __unsafe_unretained*)objects
                                     count:(NSUInteger)count {
   return [_fastEnumerationHelper->GetFastEnumeration()
       countByEnumeratingWithState:state
                           objects:objects
                             count:count];
 }
 
 #pragma mark - TabUsageRecorderDelegate
 
 - (NSUInteger)liveTabsCount {
@@ skipping 10 matching lines @@
 - (SessionIOS*)sessionForSaving {
   // Build the array of sessions. Copy the session objects as the saving will
   // be done on a separate thread.
   // TODO(crbug.com/661986): This could get expensive especially since this
   // window may never be saved (if another call comes in before the delay).
   return [[SessionIOS alloc]
       initWithWindows:@[ SerializeWebStateList(_webStateList.get()) ]];
 }
 
 - (void)postNotificationName:(NSString*)notificationName withTab:(Tab*)tab {
-  // A scoped_nsobject is used rather than an NSDictionary with static
-  // initializer dictionaryWithObject, because that approach adds the dictionary
-  // to the autorelease pool, which in turn holds Tab alive longer than
-  // necessary.
-  base::scoped_nsobject<NSDictionary> userInfo(
-      [[NSDictionary alloc] initWithObjectsAndKeys:tab, kTabModelTabKey, nil]);
-  [[NSNotificationCenter defaultCenter] postNotificationName:notificationName
-                                                      object:self
-                                                    userInfo:userInfo];
+  @autoreleasepool {

[stkhapugin, 2017/05/03 11:56:12]

Thank you very much for doing this. If you also know what is the reason for this
tab lifetime requirement, can you please file a bug and leave a todo here to
untangle this?  

[sdefresne, 2017/05/03 13:03:10]

This method was never invoked, so instead I just removed it.

+    NSDictionary* userInfo = @{kTabModelTabKey : tab};
+    [[NSNotificationCenter defaultCenter] postNotificationName:notificationName
+                                                        object:self
+                                                      userInfo:userInfo];
+  }
 }
 
 - (BOOL)restoreSessionWindow:(SessionWindowIOS*)window
                 persistState:(BOOL)persistState {
   DCHECK(_browserState);
   DCHECK(window);
 
   if (!window.sessions.count)
     return NO;
 
   int oldCount = _webStateList->count();
   DCHECK_GE(oldCount, 0);
 
   web::WebState::CreateParams createParams(_browserState);
   DeserializeWebStateList(
       _webStateList.get(), window,
       base::BindRepeating(&web::WebState::CreateWithStorageSession,
                           createParams));
 
   DCHECK_GT(_webStateList->count(), oldCount);
   int restoredCount = _webStateList->count() - oldCount;
   DCHECK_EQ(window.sessions.count, static_cast<NSUInteger>(restoredCount));
 
   scoped_refptr<web::CertificatePolicyCache> policyCache =
       web::BrowserState::GetCertificatePolicyCache(_browserState);
 
-  base::scoped_nsobject<NSMutableArray<Tab*>> restoredTabs(
-      [[NSMutableArray alloc] initWithCapacity:window.sessions.count]);
+  NSMutableArray<Tab*>* restoredTabs =
+      [[NSMutableArray alloc] initWithCapacity:window.sessions.count];
 
   for (int index = oldCount; index < _webStateList->count(); ++index) {
     web::WebState* webState = _webStateList->GetWebStateAt(index);
     Tab* tab = LegacyTabHelper::GetTabForWebState(webState);
 
     webState->SetWebUsageEnabled(webUsageEnabled_ ? true : false);
     tab.webController.usePlaceholderOverlay = YES;
 
     // Restore the CertificatePolicyCache (note that webState is invalid after
     // passing it via move semantic to -initWithWebState:model:).
     UpdateCertificatePolicyCacheFromWebState(policyCache, [tab webState]);
     [restoredTabs addObject:tab];
   }
 
   // If there was only one tab and it was the new tab page, clobber it.
   BOOL closedNTPTab = NO;
   if (oldCount == 1) {
     Tab* tab = [self tabAtIndex:0];
     if (tab.url == GURL(kChromeUINewTabURL)) {
       [self closeTab:tab];
       closedNTPTab = YES;
       oldCount = 0;
     }
   }
   if (_tabUsageRecorder)
-    _tabUsageRecorder->InitialRestoredTabs(self.currentTab, restoredTabs.get());
+    _tabUsageRecorder->InitialRestoredTabs(self.currentTab, restoredTabs);
   return closedNTPTab;
 }
 
 #pragma mark - Notification Handlers
 
 // Called when UIApplicationWillResignActiveNotification is received.
 - (void)willResignActive:(NSNotification*)notify {
   if (webUsageEnabled_ && self.currentTab) {
     [[SnapshotCache sharedInstance]
         willBeSavedGreyWhenBackgrounding:self.currentTab.tabId];
@@ skipping 28 matching lines @@
 }
 
 // Called when UIApplicationWillEnterForegroundNotification is received.
 - (void)applicationWillEnterForeground:(NSNotification*)notify {
   if (_tabUsageRecorder) {
     _tabUsageRecorder->AppWillEnterForeground();
   }
 }
 
 @end