[ios] Change WebStateList serialization method to use SessionWindowIOS.

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>
 
@@ skipping 682 matching lines @@
 
 - (SessionIOS*)sessionForSaving {
   // Background tabs will already have their state preserved, but not the
   // fg tab. Do it now.
   [self.currentTab recordStateInHistory];
 
   // 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).
-  SessionWindowIOS* sessionWindow = [[[SessionWindowIOS alloc]
-      initWithSessions:SerializeWebStateList(_webStateList.get())
-         selectedIndex:[self indexOfTab:self.currentTab]] autorelease];
-  return [[SessionIOS alloc] initWithWindows:@[ sessionWindow ]];
+  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];
 }
 
 - (BOOL)restoreSessionWindow:(SessionWindowIOS*)window
                 persistState:(BOOL)persistState {
   DCHECK(_browserState);
   DCHECK(window);
 
-  NSArray* sessions = window.sessions;
-  if (!sessions.count)
+  if (!window.sessions.count)
     return NO;
 
   int oldCount = _webStateList->count();
   DCHECK_GE(oldCount, 0);
 
+  if (persistState && self.currentTab)
+    [self.currentTab recordStateInHistory];
+
   web::WebState::CreateParams createParams(_browserState);
   DeserializeWebStateList(
-      _webStateList.get(), sessions,
+      _webStateList.get(), window,
       base::BindRepeating(&web::WebState::CreateWithStorageSession,
                           createParams));
 
   DCHECK_GT(_webStateList->count(), oldCount);
   int restoredCount = _webStateList->count() - oldCount;
-  DCHECK_EQ(sessions.count, static_cast<NSUInteger>(restoredCount));
+  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:sessions.count]);
+      [[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];
   }
 
-  // Update the selected tab if there was a selected Tab in the saved session.
-  if (window.selectedIndex != NSNotFound) {
-    NSUInteger selectedIndex = window.selectedIndex + oldCount;
-    DCHECK_LT(selectedIndex, self.count);
-    DCHECK([self tabAtIndex:selectedIndex]);
-
-    if (persistState && self.currentTab)
-      [self.currentTab recordStateInHistory];
-    _webStateList->ActivateWebStateAt(static_cast<int>(selectedIndex));
-  }
-
   // 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;
     }
   }
@@ skipping 40 matching lines @@
 }
 
 // Called when UIApplicationWillEnterForegroundNotification is received.
 - (void)applicationWillEnterForeground:(NSNotification*)notify {
   if (_tabUsageRecorder) {
     _tabUsageRecorder->AppWillEnterForeground();
   }
 }
 
 @end