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

ios/chrome/app/main_controller.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 "ios/chrome/app/main_controller.h"
 
 #include <memory>
 #include <string>
 
 #import <CoreSpotlight/CoreSpotlight.h>
@@ skipping 662 matching lines @@
   BOOL postCrashLaunch = [self mustShowRestoreInfobar];
   if (postCrashLaunch) {
     _restoreHelper =
         [[CrashRestoreHelper alloc] initWithBrowserState:chromeBrowserState];
     [_restoreHelper moveAsideSessionInformation];
   }
 
   // Initialize and set the main browser state.
   [self initializeBrowserState:chromeBrowserState];
   _mainBrowserState = chromeBrowserState;
-  [_browserViewWrangler shutdown];
   _browserViewWrangler =
       [[BrowserViewWrangler alloc] initWithBrowserState:_mainBrowserState
                                        tabModelObserver:self];
   // Ensure the main tab model is created.
   ignore_result([_browserViewWrangler mainTabModel]);
 
   _spotlightManager =
       [SpotlightManager spotlightManagerWithBrowserState:_mainBrowserState];
 
   ShareExtensionService* service =
@@ skipping 210 matching lines @@
 - (void)activateFirstUserActionRecorderWithBackgroundTime:
     (NSTimeInterval)backgroundTime {
   base::TimeDelta delta = base::TimeDelta::FromSeconds(backgroundTime);
   _firstUserActionRecorder.reset(new FirstUserActionRecorder(delta));
 }
 
 - (void)stopChromeMain {
   [_spotlightManager shutdown];
   _spotlightManager = nil;
 
-  [_browserViewWrangler shutdown];
   _browserViewWrangler = nil;
 
   _chromeMain.reset();
 }
 
 - (BOOL)isTabSwitcherActive {
   return _tabSwitcherIsActive;
 }
 
 #pragma mark - BrowserViewInformation implementation.
@@ skipping 1621 matching lines @@
       newChromeAppStartupParametersWithURL:net::NSURLWithGURL(launchURL)
                      fromSourceApplication:sourceApplication];
 }
 
 - (void)setUpAsForegrounded {
   _isColdStart = NO;
   _browserInitializationStage = INITIALIZATION_STAGE_FOREGROUND;
   // Create a BrowserViewWrangler with a null browser state. This will trigger
   // assertions if the BrowserViewWrangler is asked to create any BVC or
   // tabModel objects, but it will accept assignments to them.
-  [_browserViewWrangler shutdown];
   _browserViewWrangler =
       [[BrowserViewWrangler alloc] initWithBrowserState:nullptr
                                        tabModelObserver:self];
   // This is a test utility method that bypasses the ususal setup steps, so
   // verify that the main coordinator hasn't been created yet, then start it
   // via lazy initialization.
   DCHECK(!_mainCoordinator);
   [self.mainCoordinator start];
 }
 
@@ skipping 14 matching lines @@
   };
 
   callbackCounter->IncrementCount();
   [self removeBrowsingDataFromBrowserState:_mainBrowserState
                                       mask:removeAllMask
                                 timePeriod:browsing_data::TimePeriod::ALL_TIME
                          completionHandler:decrementCallbackCounterCount];
 }
 
 @end