Cleanup: have common HttpResponseHeaders routine to update with range

net/http/http_response_headers.h

Index: net/http/http_response_headers.h
diff --git a/net/http/http_response_headers.h b/net/http/http_response_headers.h
index deba3b6d974fd45c42f20d8b7f94b14182d1573f..2eb0c672017734b7c5af3be59292d7892f0a4f99 100644
--- a/net/http/http_response_headers.h
+++ b/net/http/http_response_headers.h
@@ -26,6 +26,8 @@ class TimeDelta;
 
 namespace net {
 
+class HttpByteRange;
+
 // HttpResponseHeaders: parses and holds HTTP response headers.
 class NET_EXPORT HttpResponseHeaders
     : public base::RefCountedThreadSafe<HttpResponseHeaders> {
@@ -83,6 +85,15 @@ class NET_EXPORT HttpResponseHeaders
   // not have any EOL).
   void ReplaceStatusLine(const std::string& new_status);
 
+  // Updates headers (Content-Length and Content-Range) in the |headers| to
+  // include the right content length and range for |byte_range|.  This also
+  // updates HTTP status line if |replace_status_line| is true.
+  // |byte_range| must have a valid, bounded range (i.e. coming from a valid
+  // response or should be usable for a response).
+  void UpdateWithNewRange(const HttpByteRange& byte_range,
+                          int64 resource_size,
+                          bool replace_status_line);
+
   // Creates a normalized header string.  The output will be formatted exactly
   // like so:
   //     HTTP/<version> <status_code> <status_text>\n