Replace deprecated base::NonThreadSafe in content/browser/appcache in favor of SequenceChecker.

content/browser/appcache/appcache_request.h

 // Copyright (c) 2017 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.
 
 #ifndef CONTENT_BROWSER_APPCACHE_APPCACHE_REQUEST_H_
 #define CONTENT_BROWSER_APPCACHE_APPCACHE_REQUEST_H_
 
 #include "base/logging.h"
+#include "base/sequence_checker.h"
 #include "base/strings/string16.h"
-#include "base/threading/non_thread_safe.h"
 #include "content/common/content_export.h"
 #include "url/gurl.h"
 
 namespace net {
 class URLRequest;
 }
 
 namespace content {
 struct ResourceRequest;
 
 // Interface for an AppCache request. Subclasses implement this interface to
 // wrap custom request objects like URLRequest, etc to ensure that these
 // dependencies stay out of the AppCache code.
-class CONTENT_EXPORT AppCacheRequest
-    : NON_EXPORTED_BASE(public base::NonThreadSafe) {
+class CONTENT_EXPORT AppCacheRequest {
  public:
-  virtual ~AppCacheRequest() {}
+  virtual ~AppCacheRequest();
 
   // The URL for this request.
   virtual const GURL& GetURL() const = 0;
 
   // The method for this request
   virtual const std::string& GetMethod() const = 0;
 
   // Used for cookie policy.
   virtual const GURL& GetFirstPartyForCookies() const = 0;
 
@@ skipping 28 matching lines @@
 
   AppCacheRequest() {}
 
   // Getters for the request types we currently support.
   virtual net::URLRequest* GetURLRequest();
 
   // Returns the underlying ResourceRequest. Please note that only one of
   // GetURLRequest() and GetResourceRequest() should return valid results.
   virtual ResourceRequest* GetResourceRequest();
 
+  SEQUENCE_CHECKER(sequence_checker_);
+
   DISALLOW_COPY_AND_ASSIGN(AppCacheRequest);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_APPCACHE_APPCACHE_REQUEST_H_