Add a new priority level, THROTTLED, below IDLE.

chrome/browser/predictors/resource_prefetch_predictor.proto

 // Copyright 2016 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.
 
 // Protocol buffers used for storing in SQLite.
 // CAUTION: When any change is done here, bump kDatabaseVersion in
 //          resource_prefetch_predictor_tables.h.
 
 syntax = "proto2";
 
@@ skipping 22 matching lines @@
     RESOURCE_TYPE_XHR = 13;
     RESOURCE_TYPE_PING = 14;
     RESOURCE_TYPE_SERVICE_WORKER = 15;
     RESOURCE_TYPE_CSP_REPORT = 16;
     RESOURCE_TYPE_PLUGIN_RESOURCE = 17;
     RESOURCE_TYPE_LAST_TYPE = 18;
   }
 
   // Mirrors net::RequestPriority
   enum Priority {
-    REQUEST_PRIORITY_IDLE = 0;
-    REQUEST_PRIORITY_LOWEST = 1;
-    REQUEST_PRIORITY_LOW = 2;
-    REQUEST_PRIORITY_MEDIUM = 3;
-    REQUEST_PRIORITY_HIGHEST = 4;
+    REQUEST_PRIORITY_THROTTLED = 0;
+    REQUEST_PRIORITY_IDLE = 1;
+    REQUEST_PRIORITY_LOWEST = 2;
+    REQUEST_PRIORITY_LOW = 3;
+    REQUEST_PRIORITY_MEDIUM = 4;
+    REQUEST_PRIORITY_HIGHEST = 5;
   }
 
   optional string resource_url = 1;
   optional ResourceType resource_type = 2;
   optional uint32 number_of_hits = 3;
   optional uint32 number_of_misses = 4;
   optional uint32 consecutive_misses = 5;
   optional double average_position = 6;
   optional Priority priority = 7;
   optional bool has_validators = 8;
@@ skipping 17 matching lines @@
     optional uint32 number_of_hits = 2;
     optional uint32 number_of_misses = 3;
     optional uint32 consecutive_misses = 4;
   }
 
   // Main frame URL or host.
   optional string primary_key = 1;
   optional uint64 last_visit_time = 2;
   repeated RedirectStat redirect_endpoints = 3;
 }