Implement 1:N mapping from ios::ChromeBrowserState to TabModel.

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 <list>
 #include <utility>
 #include <vector>
 
@@ skipping 12 matching lines @@
 #include "ios/chrome/browser/browser_state/chrome_browser_state.h"
 #include "ios/chrome/browser/chrome_url_constants.h"
 #import "ios/chrome/browser/chrome_url_util.h"
 #import "ios/chrome/browser/metrics/tab_usage_recorder.h"
 #include "ios/chrome/browser/sessions/ios_chrome_tab_restore_service_factory.h"
 #import "ios/chrome/browser/sessions/session_service.h"
 #import "ios/chrome/browser/sessions/session_window.h"
 #import "ios/chrome/browser/snapshots/snapshot_cache.h"
 #include "ios/chrome/browser/tab_parenting_global_observer.h"
 #import "ios/chrome/browser/tabs/tab.h"
+#import "ios/chrome/browser/tabs/tab_model_list.h"
 #import "ios/chrome/browser/tabs/tab_model_observer.h"
 #import "ios/chrome/browser/tabs/tab_model_order_controller.h"
 #import "ios/chrome/browser/tabs/tab_model_synced_window_delegate.h"
 #import "ios/chrome/browser/xcallback_parameters.h"
 #import "ios/web/navigation/crw_session_certificate_policy_manager.h"
 #import "ios/web/navigation/crw_session_controller.h"
 #include "ios/web/public/browser_state.h"
 #include "ios/web/public/certificate_policy_cache.h"
 #include "ios/web/public/navigation_item.h"
 #import "ios/web/public/navigation_manager.h"
@@ skipping 249 matching lines @@
     // Register for background notification.
     [defaultCenter addObserver:self
                       selector:@selector(applicationDidEnterBackground:)
                           name:UIApplicationDidEnterBackgroundNotification
                         object:nil];
     // Register for foregrounding notification.
     [defaultCenter addObserver:self
                       selector:@selector(applicationWillEnterForeground:)
                           name:UIApplicationWillEnterForegroundNotification
                         object:nil];
+
+    // Associate with ios::ChromeBrowserState.
+    RegisterTabModelWithChromeBrowserState(_browserState, self);
   }
   return self;
 }
 
 - (instancetype)init {
   NOTREACHED();
   return nil;
 }
 
 - (BOOL)restoreSessionWindow:(SessionWindowIOS*)window {
@@ skipping 413 matching lines @@
       NSString* fileName = base::SysUTF8ToNSString(URL.ExtractFileName());
       [referencedFiles addObject:fileName];
     }
   }
   return referencedFiles;
 }
 
 // NOTE: This can be called multiple times, so must be robust against that.
 - (void)browserStateDestroyed {
   [[NSNotificationCenter defaultCenter] removeObserver:self];
+  if (_browserState) {
+    UnregisterTabModelFromChromeBrowserState(_browserState, self);
+  }
   _browserState = nullptr;
 }
 
 // Called when a tab is closing, but before its CRWWebController is destroyed.
 // Equivalent to DetachTabContentsAt() in Chrome's TabStripModel.
 - (void)didCloseTab:(Tab*)closedTab {
   NSUInteger closedTabIndex = [_tabs indexOfObject:closedTab];
   DCHECK(closedTab);
   DCHECK(closedTabIndex != NSNotFound);
   // Let the sessions::TabRestoreService know about that new tab.
@@ skipping 313 matching lines @@
   web::NavigationManager::WebLoadParams params(URL);
   params.referrer = referrer;
   params.transition_type = ui::PAGE_TRANSITION_TYPED;
   [[tab webController] loadWithParams:params];
   [tab webController].webUsageEnabled = webUsageEnabled_;
   [self insertTab:tab atIndex:index];
   return tab;
 }
 
 @end