Adds UMA metrics for renderer uptime

chrome/browser/BUILD.gn

 # 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.
 
 import("//build/config/chrome_build.gni")
 import("//build/config/crypto.gni")
 import("//build/config/features.gni")
 import("//build/config/ui.gni")
 import("//build/split_static_library.gni")
 import("//chrome/common/features.gni")
@@ skipping 598 matching lines @@
     "metrics/jumplist_metrics_win.cc",
     "metrics/jumplist_metrics_win.h",
     "metrics/metrics_memory_details.cc",
     "metrics/metrics_memory_details.h",
     "metrics/metrics_reporting_state.cc",
     "metrics/metrics_reporting_state.h",
     "metrics/network_quality_estimator_provider_impl.cc",
     "metrics/network_quality_estimator_provider_impl.h",
     "metrics/perf/perf_provider_chromeos.cc",
     "metrics/perf/perf_provider_chromeos.h",
+    "metrics/renderer_uptime_tracker.cc",
+    "metrics/renderer_uptime_tracker.h",
+    "metrics/renderer_uptime_web_contents_observer.cc",
+    "metrics/renderer_uptime_web_contents_observer.h",
     "metrics/sampling_metrics_provider.cc",
     "metrics/sampling_metrics_provider.h",
     "metrics/subprocess_metrics_provider.cc",
     "metrics/subprocess_metrics_provider.h",
     "metrics/thread_watcher.cc",
     "metrics/thread_watcher.h",
     "metrics/thread_watcher_android.cc",
     "metrics/thread_watcher_android.h",
     "metrics/thread_watcher_report_hang.cc",
     "metrics/thread_watcher_report_hang.h",
@@ skipping 3908 matching lines @@
       "media/pepper_cdm_test_constants.cc",
       "media/pepper_cdm_test_constants.h",
     ]
   }
 }
 
 service_manifest("preferences_manifest") {
   name = "preferences"
   source = "prefs/preferences_manifest.json"
 }