[ios] Removed network stack related code from ios_web_shell's VC.

ios/web/shell/view_controller.mm

Index: ios/web/shell/view_controller.mm
diff --git a/ios/web/shell/view_controller.mm b/ios/web/shell/view_controller.mm
index d4b22c74fcdb81025d5f7d2ba45766d10962097a..c4a0d068cf6bc41907094d731714efbe44ff6a30 100644
--- a/ios/web/shell/view_controller.mm
+++ b/ios/web/shell/view_controller.mm
@@ -13,9 +13,6 @@
 
 #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"
@@ -62,11 +59,6 @@ using web::NavigationManager;
   return self;
 }
 
-- (void)dealloc {
-  net::HTTPProtocolHandlerDelegate::SetInstance(nullptr);
-  net::RequestTracker::SetRequestTrackerFactory(nullptr);
-}
-
 - (void)viewDidLoad {
   [super viewDidLoad];
 
@@ -132,9 +124,6 @@ using web::NavigationManager;
   [_toolbarView addSubview:forward];
   [_toolbarView addSubview:field];
 
-  // Set up the network stack before creating the WebState.
-  [self setUpNetworkStack];
-
   web::WebState::CreateParams webStateCreateParams(_browserState);
   _webState = web::WebState::Create(webStateCreateParams);
   _webState->SetWebUsageEnabled(true);
@@ -161,11 +150,6 @@ using web::NavigationManager;
   return _webState.get();
 }
 
-- (void)setUpNetworkStack {
-  // Disable the default cache.
-  [NSURLCache setSharedURLCache:[EmptyNSURLCache emptyNSURLCache]];
-}
-
 - (void)didReceiveMemoryWarning {
   [super didReceiveMemoryWarning];
 }