Move the notion of current Tab from TabModel to WebStateList.

ios/chrome/browser/ui/browser_view_controller.mm

Index: ios/chrome/browser/ui/browser_view_controller.mm
diff --git a/ios/chrome/browser/ui/browser_view_controller.mm b/ios/chrome/browser/ui/browser_view_controller.mm
index 767fdea5744bd638740d557735b4c0feb54cd2a9..9fc667da391785635f28eda253bf655d50b5078e 100644
--- a/ios/chrome/browser/ui/browser_view_controller.mm
+++ b/ios/chrome/browser/ui/browser_view_controller.mm
@@ -3606,9 +3606,7 @@ class BrowserBookmarkModelBridge : public bookmarks::BookmarkModelObserver {
       // 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;
     }
@@ -4581,8 +4579,7 @@ class BrowserBookmarkModelBridge : public bookmarks::BookmarkModelObserver {
     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) {