Move the notion of current Tab from TabModel to WebStateList.

ios/chrome/browser/ui/browser_view_controller.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/ui/browser_view_controller.h"
 
 #import <AssetsLibrary/AssetsLibrary.h>
 #import <MobileCoreServices/MobileCoreServices.h>
 #import <PassKit/PassKit.h>
 #import <Photos/Photos.h>
@@ skipping 3588 matching lines @@
       [newHistory insertStateFromSessionController:oldHistory];
       [[newTab nativeAppNavigationController]
           copyStateFrom:[oldTab nativeAppNavigationController]];
       [_model replaceTab:oldTab withTab:newTab];
 
       // Set isPrerenderTab to NO after replacing the tab. This will allow the
       // BrowserViewController to detect that a pre-rendered tab is switched in,
       // and show the prerendering animation.
       newTab.isPrerenderTab = NO;
 
-      BOOL loadingFinished =
-          [newTab.webController loadPhase] == web::PAGE_LOADED;
-      [self tabLoadComplete:newTab withSuccess:loadingFinished];
+      [self tabLoadComplete:newTab withSuccess:newTab.loadFinished];
 
       return;
     }
   }
 
   GURL urlToLoad = url;
   if ([_preloadController hasPrefetchedURL:url]) {
     // Prefetched URLs have modified URLs, so load the prefetched version of
     // |url| instead of the original |url|.
     urlToLoad = [_preloadController prefetchedURL];
@@ skipping 952 matching lines @@
 
     // Set isPrerenderTab to NO after inserting the tab. This will allow the
     // BrowserViewController to detect that a pre-rendered tab is switched in,
     // and show the prerendering animation. This needs to happen before the
     // tab is made the current tab.
     // This also enables contextual search (if otherwise applicable) on
     // |newTab|.
     newTab.isPrerenderTab = NO;
     [_model setCurrentTab:newTab];
 
-    BOOL loadingFinished = [newTab.webController loadPhase] == web::PAGE_LOADED;
-    if (loadingFinished)
+    if (newTab.loadFinished)
       [self tabLoadComplete:newTab withSuccess:YES];
 
     if (focusInput) {
       [_toolbarController focusOmnibox];
     }
     _infoBarContainer->RestoreInfobars();
 
     [UIView animateWithDuration:ios::material::kDuration2
         animations:^{
           promotingPanel.alpha = 0;
@@ skipping 429 matching lines @@
 
 - (UIView*)voiceSearchButton {
   return _voiceSearchButton;
 }
 
 - (id<LogoAnimationControllerOwner>)logoAnimationControllerOwner {
   return [self currentLogoAnimationControllerOwner];
 }
 
 @end