Suppress pause-and-buffer behavior when the HTTP response won't satisfy future requests via cache.

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 57aa0d005fded58cebcf0fc8b354fc01f2065056..23ac02a0f5ae1a6dd4495c06fc01517462055824 100644
--- a/net/http/http_util.h
+++ b/net/http/http_util.h
@@ -14,6 +14,7 @@
 #include "googleurl/src/gurl.h"
 #include "net/base/net_export.h"
 #include "net/http/http_byte_range.h"
+#include "net/http/http_version.h"
 
 // This is a macro to support extending this string literal at compile time.
 // Please excuse me polluting your global namespace!
@@ -187,6 +188,13 @@ class NET_EXPORT HttpUtil {
                                     const std::string& header_value,
                                     std::string* headers);
 
+  // Returns true if this response has a strong etag or last-modified header.
+  // See section 13.3.3 of RFC 2616.
+  static bool HasStrongValidators(HttpVersion version,
+                                  const std::string& etag_header,
+                                  const std::string& last_modified_header,
+                                  const std::string& date_header);
+
   // Used to iterate over the name/value pairs of HTTP headers.  To iterate
   // over the values in a multi-value header, use ValuesIterator.
   // See AssembleRawHeaders for joining line continuations (this iterator