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 13209b8f421fd5bfb7a78e4ff407807302215e0b..6daf69942eedd8551d909d20f2f7c9daee5a78b4 100644
--- a/net/http/http_util.h
+++ b/net/http/http_util.h
@@ -210,6 +210,13 @@ 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).