ServiceWorker: Enable UseCounter for ServiceWorkerGlobalScope

content/browser/service_worker/service_worker_database.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 32 matching lines @@
   repeated string foreign_fetch_scope = 9;
   repeated string foreign_fetch_origin = 10;
 
   // If the registration data was created by old Chrome (< M56),
   // |origin_trial_tokens| is not set. In this case, we have to start the
   // Service Worker and load the main script resource in ServiceWorkerStorage
   // to check the HTTP header.
   optional ServiceWorkerOriginTrialInfo origin_trial_tokens = 11;
 
   optional ServiceWorkerNavigationPreloadState navigation_preload_state = 12;
+
+  // The set of features that the worker has used. The values must be from
+  // blink::UseCounter::Feature enum.

[falken, 2017/02/08 05:01:53]

This is the set of features the worker used up until the time installation
completed right? Could the comment reflect that?

[nhiroki, 2017/02/09 05:11:31]

That's right. Updated.

+  repeated uint32 used_features = 13;
 }
 
 message ServiceWorkerResourceRecord {
   required int64 resource_id = 1;
   required string url = 2;
   optional uint64 size_bytes = 3;
 }