Add Startup.BrowserView.FirstPaint / .CompositingEnded histograms.

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 586 matching lines @@
     "memory/chrome_memory_coordinator_delegate.cc",
     "memory/chrome_memory_coordinator_delegate.h",
     "memory_details.cc",
     "memory_details.h",
     "memory_details_android.cc",
     "memory_details_linux.cc",
     "memory_details_mac.cc",
     "memory_details_win.cc",
     "metrics/antivirus_metrics_provider_win.cc",
     "metrics/antivirus_metrics_provider_win.h",
+    "metrics/browser_window_histogram_helper.cc",
+    "metrics/browser_window_histogram_helper.h",
     "metrics/chrome_browser_main_extra_parts_metrics.cc",
     "metrics/chrome_browser_main_extra_parts_metrics.h",
     "metrics/chrome_browser_main_extra_parts_metrics_mac.mm",
     "metrics/chrome_metrics_service_accessor.cc",
     "metrics/chrome_metrics_service_accessor.h",
     "metrics/chrome_metrics_service_client.cc",
     "metrics/chrome_metrics_service_client.h",
     "metrics/chrome_metrics_services_manager_client.cc",
     "metrics/chrome_metrics_services_manager_client.h",
     "metrics/chrome_stability_metrics_provider.cc",
@@ skipping 4073 matching lines @@
       "media/pepper_cdm_test_constants.cc",
       "media/pepper_cdm_test_constants.h",
     ]
   }
 }
 
 service_manifest("preferences_forwarder_manifest") {
   name = "preferences_forwarder"
   source = "prefs/forwarder_manifest.json"
 }