[CacheStorage] Sort QueryCache results by time entered into cache

content/browser/cache_storage/cache_storage.proto

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 syntax = "proto2";
 
 option optimize_for = LITE_RUNTIME;
 
 package content;
 
@@ skipping 31 matching lines @@
   required ResponseType response_type = 3;
   repeated CacheHeaderMap headers = 4;
   optional string url = 5;
   optional int64 response_time = 6;
   repeated string cors_exposed_header_names = 7;
 }
 
 message CacheMetadata {
   required CacheRequest request = 1;
   required CacheResponse response = 2;
+  optional int64 entry_time = 3;
 }