Move AddMultipartValueForUpload to net/base/mime_util.h/cc.

net/base/mime_util.h

Index: net/base/mime_util.h
diff --git a/net/base/mime_util.h b/net/base/mime_util.h
index d2638cb3a6d9d4743457b75fedae8f808275d634..6be693da31c74a161c78ac898ec27bf5c82a3a94 100644
--- a/net/base/mime_util.h
+++ b/net/base/mime_util.h
@@ -119,6 +119,13 @@ enum CertificateMimeType {
 NET_EXPORT CertificateMimeType GetCertificateMimeTypeForMimeType(
     const std::string& mime_type);
 
+// Prepares one value as part of a multi-part upload request.
+NET_EXPORT void AddMultipartValueForUpload(const std::string& value_name,
+                                           const std::string& value,
+                                           const std::string& mime_boundary,
+                                           const std::string& content_type,
+                                           std::string* post_data);
+
 }  // namespace net
 
 #endif  // NET_BASE_MIME_UTIL_H__