Compute ResourceResponse::suggestedFileName on the fly.

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

Index: third_party/WebKit/Source/platform/network/NetworkUtils.h
diff --git a/third_party/WebKit/Source/platform/network/NetworkUtils.h b/third_party/WebKit/Source/platform/network/NetworkUtils.h
index d59f454735f0a06c068bb32242c4b8c78351c88f..c262e382bf4d35cb0d7c40739ffa9d34d8418ffc 100644
--- a/third_party/WebKit/Source/platform/network/NetworkUtils.h
+++ b/third_party/WebKit/Source/platform/network/NetworkUtils.h
@@ -6,6 +6,7 @@
 #define NetworkUtils_h
 
 #include "platform/PlatformExport.h"
+#include "platform/weborigin/KURL.h"
 #include "wtf/Forward.h"
 
 namespace blink {
@@ -24,6 +25,10 @@ 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