MD Bookmarks: Add a metric to measure load-time performance

extensions/common/api/_api_features.json

 // 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.
 
 // This features file defines extension APIs implemented under src/extensions.
 // See chrome/common/extensions/api/_features.md to understand this file, as
 // well as feature.h, simple_feature.h, and feature_provider.h.
 //
 // Note that specifying "web_page", "blessed_web_page", or "all" as a context
 // type will require manually updating chrome/renderer/resources/dispatcher.cc.
@@ skipping 230 matching lines @@
     "contexts": ["blessed_extension"]
   },
   "metricsPrivate": [{
     "dependencies": ["permission:metricsPrivate"],
     "contexts": ["blessed_extension"],
     "default_parent": true
   }, {
     "channel": "stable",
     "contexts": ["webui"],
     "matches": [
+      "chrome://bookmarks/*",
       "chrome://md-settings/*",
       "chrome://settings/*",
       "chrome://settings-frame/*"
     ]
   }],
   "metricsPrivate.getIsCrashReportingEnabled": {
     "whitelist": [
       // This function inherits the extension restrictions of metricsPrivate,
       // but also requires whitelisting. New uses of this function should get
       // /tools/metrics/OWNERS approval of the usage before adding entries
@@ skipping 276 matching lines @@
   }, {
     "channel": "stable",
     "contexts": ["webui"],
     "matches": [
       "chrome://chrome-signin/*",
       "chrome://media-router/*",
       "chrome://oobe/*"
     ]
   }]
 }