ServiceWorker: Add UMA for ServiceWorkerDiskCache

content/content_browser.gypi

 # Copyright (c) 2012 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.
 
 {
   'dependencies': [
     '../base/base.gyp:base_static',
     '../crypto/crypto.gyp:crypto',
     '../google_apis/google_apis.gyp:google_apis',
     '../net/net.gyp:net',
@@ skipping 1171 matching lines @@
       'browser/service_worker/service_worker_database.cc',
       'browser/service_worker/service_worker_database.h',
       'browser/service_worker/service_worker_disk_cache.cc',
       'browser/service_worker/service_worker_disk_cache.h',
       'browser/service_worker/service_worker_dispatcher_host.cc',
       'browser/service_worker/service_worker_dispatcher_host.h',
       'browser/service_worker/service_worker_fetch_dispatcher.cc',
       'browser/service_worker/service_worker_fetch_dispatcher.h',
       'browser/service_worker/service_worker_handle.cc',
       'browser/service_worker/service_worker_handle.h',
+      'browser/service_worker/service_worker_histograms.cc',
+      'browser/service_worker/service_worker_histograms.h',
       'browser/service_worker/service_worker_info.cc',
       'browser/service_worker/service_worker_info.h',
       'browser/service_worker/service_worker_internals_ui.cc',
       'browser/service_worker/service_worker_internals_ui.h',
       'browser/service_worker/service_worker_job_coordinator.cc',
       'browser/service_worker/service_worker_job_coordinator.h',
       'browser/service_worker/service_worker_process_manager.cc',
       'browser/service_worker/service_worker_process_manager.h',
       'browser/service_worker/service_worker_provider_host.cc',
       'browser/service_worker/service_worker_provider_host.h',
@@ skipping 553 matching lines @@
         '../build/linux/system.gyp:dbus',
         '../dbus/dbus.gyp:dbus',
       ],
     }, {  # OS != "linux" or use_dbus==0
       'sources!': [
         'browser/geolocation/wifi_data_provider_linux.cc',
       ],
     }],
   ],
 }