[ios] WebStateList owns all WebState it manages.

ios/chrome/browser/ui/tabs/tab_strip_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>
 
 #include <memory>
 
 #include "ios/chrome/browser/browser_state/test_chrome_browser_state.h"
 #import "ios/chrome/browser/sessions/test_session_service.h"
@@ skipping 103 matching lines @@
       [invocation setReturnValue:&browser_state];
     }] browserState];
     [[tabModel stub] addObserver:[OCMArg any]];
     [[tabModel stub] removeObserver:[OCMArg any]];
 
     // Stub methods for Tabs.
     [[[tab1 stub] andReturn:@"Tab Title 1"] title];
     [[[tab2 stub] andReturn:@"Tab Title 2"] title];
     [[[tab1 stub] andReturn:nil] favicon];
     [[[tab2 stub] andReturn:nil] favicon];
-    [[tab1 stub] close];
-    [[tab2 stub] close];
 
     tabModel_ = tabModel;
     tab1_ = tab1;
     tab2_ = tab2;
     controller_ =
         [[TabStripController alloc] initWithTabModel:(TabModel*)tabModel_
                                                style:TabStrip::kStyleDark];
 
     // Force the view to load.
     UIWindow* window = [[UIWindow alloc] initWithFrame:CGRectZero];
@@ skipping 25 matching lines @@
   ASSERT_OCMOCK_VERIFY(tab1_);
   ASSERT_OCMOCK_VERIFY(tab2_);
 
   // There should be two TabViews and one new tab button nested within the
   // parent view (which contains exactly one scroll view).
   EXPECT_EQ(3U,
             [[[[[controller_ view] subviews] objectAtIndex:0] subviews] count]);
 }
 
 }  // namespace