[ios] Change API to inform WebStateList of opener-opened relationship.

ios/shared/chrome/browser/tabs/web_state_list_order_controller.mm

 // Copyright 2017 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/shared/chrome/browser/tabs/web_state_list_order_controller.h"
 
 #include <cstdint>
 
 #include "base/logging.h"
 #import "ios/shared/chrome/browser/tabs/web_state_list.h"
+#import "ios/shared/chrome/browser/tabs/web_state_opener.h"
 
 WebStateListOrderController::WebStateListOrderController(
     WebStateList* web_state_list)
     : web_state_list_(web_state_list) {
   DCHECK(web_state_list_);
 }
 
 WebStateListOrderController::~WebStateListOrderController() = default;
 
 int WebStateListOrderController::DetermineInsertionIndex(
@@ skipping 25 matching lines @@
   DCHECK(web_state_list_->ContainsIndex(removing_index));
   // First see if the index being removed has any "child" WebState. If it does,
   // select the first WebState in that child group, not the next in the removed
   // index group.
   int index = web_state_list_->GetIndexOfNextWebStateOpenedBy(
       web_state_list_->GetWebStateAt(removing_index), removing_index, false);
 
   if (index != WebStateList::kInvalidIndex)
     return GetValidIndex(index, removing_index);
 
-  web::WebState* opener =
+  WebStateOpener opener =
       web_state_list_->GetOpenerOfWebStateAt(removing_index);
-  if (opener) {
+  if (opener.opener) {
     // If the WebState was in a group, shift selection to the next WebState in
     // the group.
     int index = web_state_list_->GetIndexOfNextWebStateOpenedBy(
-        opener, removing_index, false);
+        opener.opener, removing_index, false);
 
     if (index != WebStateList::kInvalidIndex)
       return GetValidIndex(index, removing_index);
 
     // If there is no subsequent group member, just fall back to opener itself.
-    index = web_state_list_->GetIndexOfWebState(opener);
+    index = web_state_list_->GetIndexOfWebState(opener.opener);
     return GetValidIndex(index, removing_index);
   }
 
   // If this is the last WebState in the WebStateList, clear the selection.
   if (web_state_list_->count() == 1)
     return WebStateList::kInvalidIndex;
 
   // No opener, fall through to the default handler, i.e. returning the previous
   // WebState if the removed one is the last, otherwise returning the next one.
   if (removing_index >= web_state_list_->count() - 1)
     return removing_index - 1;
 
   return removing_index;
 }
 
 int WebStateListOrderController::GetValidIndex(int index,
                                                int removing_index) const {
   if (removing_index < index)
     return std::min(0, index - 1);
   return index;
 }