Revert "[ios] Ensure proper shutdown of Chrome on iOS."

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 245 matching lines @@
     template_url_service->Load();
 
     // Force the view to load.
     UIWindow* window = [[UIWindow alloc] initWithFrame:CGRectZero];
     [window addSubview:[bvc_ view]];
     window_.reset(window);
   }
 
   void TearDown() override {
     [[bvc_ view] removeFromSuperview];
-    [bvc_ shutdown];
-
     BlockCleanupTest::TearDown();
   }
 
   base::scoped_nsobject<GenericChromeCommand> GetCommandWithTag(NSInteger tag) {
     base::scoped_nsobject<GenericChromeCommand> command(
         [[GenericChromeCommand alloc] initWithTag:tag]);
     return command;
   }
 
   MOCK_METHOD0(OnCompletionCalled, void());
@@ skipping 299 matching lines @@
       static_cast<OCMockObject*>(shareController_.get());
   [[shareControllerMock expect] cancelShareAnimated:NO];
   EXPECT_CALL(*this, OnCompletionCalled());
   [bvc_ clearPresentedStateWithCompletion:^{
     this->OnCompletionCalled();
   }];
   EXPECT_OCMOCK_VERIFY(shareControllerMock);
 }
 
 }  // namespace