Added HttpUtils::HasValidators and HttpResponse::HasValidators

net/http/http_util.h

Index: net/http/http_util.h
diff --git a/net/http/http_util.h b/net/http/http_util.h
index 1bb3c93f8ab168152dc75205e00aabcc0d9c30cf..839f6c1b15e5b69ef95339d5b6fefe183048b2fb 100644
--- a/net/http/http_util.h
+++ b/net/http/http_util.h
@@ -203,6 +203,13 @@ class NET_EXPORT HttpUtil {
                                   const std::string& last_modified_header,
                                   const std::string& date_header);
 
+  // Returns true if this response has any validator (either a Last-Modified or
+  // an ETag) regardless of whether it is strong or weak.  See section 13.3.3 of
+  // RFC 2616.
+  static bool HasValidators(HttpVersion version,
+                            const std::string& etag_header,
+                            const std::string& last_modified_header);
+
   // Gets a vector of common HTTP status codes for histograms of status
   // codes.  Currently returns everything in the range [100, 600), plus 0
   // (for invalid responses/status codes).