[ObjC ARC] Converts ios/web:web to ARC.

ios/web/web_state/web_state_delegate_bridge.mm

 // Copyright 2016 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/public/web_state/web_state_delegate_bridge.h"
 
 #include "base/logging.h"
 #import "ios/web/public/web_state/context_menu_params.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 namespace web {
 
 WebStateDelegateBridge::WebStateDelegateBridge(id<CRWWebStateDelegate> delegate)
     : delegate_(delegate) {}
 
 WebStateDelegateBridge::~WebStateDelegateBridge() {}
 
 WebState* WebStateDelegateBridge::CreateNewWebState(WebState* source,
                                                     const GURL& url,
                                                     const GURL& opener_url,
@@ skipping 73 matching lines @@
                            completionHandler:^(NSString* username,
                                                NSString* password) {
                              local_callback.Run(username, password);
                            }];
   } else {
     local_callback.Run(nil, nil);
   }
 }
 
 }  // web