Removes WeakNSObject in ARC files in ios/web.

ios/web/web_state/crw_pass_kit_downloader.mm

 // Copyright 2015 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/web_state/crw_pass_kit_downloader.h"
 
 #include <memory>
 
-#import "base/ios/weak_nsobject.h"
 #include "base/mac/scoped_block.h"
 #include "base/macros.h"
 #include "base/metrics/histogram.h"
 #include "base/strings/sys_string_conversions.h"
 #import "ios/web/crw_network_activity_indicator_manager.h"
 #include "net/http/http_response_headers.h"
 #include "net/url_request/url_fetcher.h"
 #include "net/url_request/url_fetcher_delegate.h"
 #include "net/url_request/url_request_context_getter.h"
 
@@ skipping 52 matching lines @@
 // download is complete.
 class PassKitFetcherDelegate : public URLFetcherDelegate {
  public:
   explicit PassKitFetcherDelegate(CRWPassKitDownloader* owner)
       : owner_(owner) {}
   void OnURLFetchComplete(const URLFetcher* source) override {
     [owner_ didFinishDownload];
   }
 
  private:
-  base::WeakNSObject<CRWPassKitDownloader> owner_;
+  __weak CRWPassKitDownloader* owner_;
   DISALLOW_COPY_AND_ASSIGN(PassKitFetcherDelegate);
 };
 
 }  // namespace
 
 @implementation CRWPassKitDownloader {
   // Completion handler that is called when PassKit data is downloaded.
   base::mac::ScopedBlock<web::PassKitCompletionHandler> _completionHandler;
 
   // URLFetcher with which PassKit data is downloaded. It is initialized
@@ skipping 104 matching lines @@
       stringWithFormat:@"PassKitDownloader.NetworkActivityIndicatorKey.%d",
                        _passKitDownloaderID];
 }
 
 - (void)reportUMAPassKitResult:(DownloadPassKitResult)result {
   UMA_HISTOGRAM_ENUMERATION(kUMADownloadPassKitResult, result,
                             DOWNLOAD_PASS_KIT_RESULT_COUNT);
 }
 
 @end