Use HttpRequestHeaders for extra_headers.

net/http/http_util.cc

Index: net/http/http_util.cc
diff --git a/net/http/http_util.cc b/net/http/http_util.cc
index 5ea46d074e77fc4fe5b7af6bb62c2b8d64a7ccb0..2ca8f02f439ffa2f04e658bee1989d2485259d50 100644
--- a/net/http/http_util.cc
+++ b/net/http/http_util.cc
@@ -202,6 +202,12 @@ bool HttpUtil::ParseRanges(const std::string& headers,
   if (ranges_specifier.empty())
     return false;
 
+  return ParseRangeHeader(ranges_specifier, ranges);
+}
+
+// static
+bool HttpUtil::ParseRangeHeader(const std::string& ranges_specifier,
+                                std::vector<HttpByteRange>* ranges) {
   size_t equal_char_offset = ranges_specifier.find('=');
   if (equal_char_offset == std::string::npos)
     return false;