Change creation order of TabModel observers.

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 313 matching lines @@
                        sessionService:(SessionServiceIOS*)service
                          browserState:(ios::ChromeBrowserState*)browserState {
   if ((self = [super init])) {
     _tabRetainer.reset([[NSMutableSet alloc] init]);
     _observers.reset([[TabModelObservers observers] retain]);
 
     _fastEnumerationHelper.reset([[WebStateListFastEnumerationHelper alloc]
         initWithWebStateList:&_webStateList
                 proxyFactory:[[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>(self);
+
+    // There must be a valid session service defined to consume session windows.
+    DCHECK(service);
+    _sessionService.reset([service retain]);
+
     _observerBridges.push_back(base::MakeUnique<TabParentingObserver>());
     _observerBridges.push_back(base::MakeUnique<WebStateListObserverBridge>(
         [[TabModelObserversBridge alloc] initWithTabModel:self
                                         tabModelObservers:_observers.get()]));
     _observerBridges.push_back(base::MakeUnique<WebStateListMetricsObserver>());
+
     for (const auto& observerBridge : _observerBridges)
       _webStateList.AddObserver(observerBridge.get());
 
-    _browserState = browserState;
-    DCHECK(_browserState);
-
-    // There must be a valid session service defined to consume session windows.
-    DCHECK(service);
-    _sessionService.reset([service retain]);
-
-    // 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.reset(new TabUsageRecorder(self));
-    }
-    _syncedWindowDelegate.reset(new TabModelSyncedWindowDelegate(self));
-
     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];
     }
 
     _orderController.reset(
         [[TabModelOrderController alloc] initWithTabModel:self]);
@@ skipping 765 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 opener:parentTab];
   return tab;
 }
 
 @end