[ios] WebStateList owns all WebState it manages.

ios/chrome/browser/ui/browser_view_controller_unittest.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 <Foundation/Foundation.h>
 #import <PassKit/PassKit.h>
 
 #include <memory>
 
 #include "base/command_line.h"
@@ skipping 110 matching lines @@
 
 @implementation BVCTestTabModel {
   FakeWebStateListDelegate _webStateListDelegate;
   std::unique_ptr<WebStateList> _webStateList;
 }
 
 - (instancetype)init {
   if ((self = [super
            initWithRepresentedObject:[OCMockObject
                                          niceMockForClass:[TabModel class]]])) {
-    _webStateList = base::MakeUnique<WebStateList>(&_webStateListDelegate,
-                                                   WebStateList::WebStateOwned);
+    _webStateList = base::MakeUnique<WebStateList>(&_webStateListDelegate);
   }
   return self;
 }
 
 - (WebStateList*)webStateList {
   return _webStateList.get();
 }
 @end
 
 #pragma mark -
@@ skipping 422 matching lines @@
       static_cast<OCMockObject*>(shareController_.get());
   [[shareControllerMock expect] cancelShareAnimated:NO];
   EXPECT_CALL(*this, OnCompletionCalled());
   [bvc_ clearPresentedStateWithCompletion:^{
     this->OnCompletionCalled();
   }];
   EXPECT_OCMOCK_VERIFY(shareControllerMock);
 }
 
 }  // namespace