Compute ResourceResponse::suggestedFileName on the fly.

third_party/WebKit/Source/platform/network/NetworkUtils.h

 // 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.
 
 #ifndef NetworkUtils_h
 #define NetworkUtils_h
 
 #include "platform/PlatformExport.h"
+#include "platform/weborigin/KURL.h"
 #include "wtf/Forward.h"
 
 namespace blink {
 
 namespace NetworkUtils {
 
 enum PrivateRegistryFilter {
   IncludePrivateRegistries,
   ExcludePrivateRegistries,
 };
 
 PLATFORM_EXPORT bool isReservedIPAddress(const String& host);
 
 PLATFORM_EXPORT bool isLocalHostname(const String& host, bool* isLocal6);
 
 PLATFORM_EXPORT String getDomainAndRegistry(const String& host,
                                             PrivateRegistryFilter);
 
+// |contentDisposition| should be retrieved from response headers.
+PLATFORM_EXPORT String getSuggestedFilename(const KURL&,
+                                            const String& contentDisposition);
+
 }  // NetworkUtils
 
 }  // namespace blink
 
 #endif  // NetworkUtils_h