Remove support for custom NSURLProtocol.

ios/web/shell/view_controller.mm

 // Copyright 2014 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/web/shell/view_controller.h"
 
 #import <MobileCoreServices/MobileCoreServices.h>
 
 #include <stdint.h>
 
 #include <memory>
 #include <utility>
 
 #import "base/mac/scoped_nsobject.h"
 #include "base/strings/sys_string_conversions.h"
-#import "ios/net/crn_http_protocol_handler.h"
 #import "ios/net/empty_nsurlcache.h"
 #import "ios/net/request_tracker.h"
 #import "ios/web/public/navigation_manager.h"
 #include "ios/web/public/referrer.h"
 #import "ios/web/public/web_state/context_menu_params.h"
 #import "ios/web/public/web_state/web_state.h"
 #import "ios/web/public/web_state/web_state_delegate_bridge.h"
 #import "ios/web/public/web_state/web_state_observer_bridge.h"
 #import "net/base/mac/url_conversions.h"
 #include "ui/base/page_transition_types.h"
@@ skipping 29 matching lines @@
 
 - (instancetype)initWithBrowserState:(web::BrowserState*)browserState {
   self = [super initWithNibName:nil bundle:nil];
   if (self) {
     _browserState = browserState;
   }
   return self;
 }
 
 - (void)dealloc {
-  net::HTTPProtocolHandlerDelegate::SetInstance(nullptr);
   net::RequestTracker::SetRequestTrackerFactory(nullptr);
 }
 
 - (void)viewDidLoad {
   [super viewDidLoad];
 
   CGRect bounds = self.view.bounds;
 
   // Set up the toolbar.
   _toolbarView = [[UIToolbar alloc] init];
@@ skipping 241 matching lines @@
   [alert addAction:[UIAlertAction actionWithTitle:@"Cancel"
                                             style:UIAlertActionStyleCancel
                                           handler:nil]];
 
   [self presentViewController:alert animated:YES completion:nil];
 
   return YES;
 }
 
 @end