Add WebAPK installation metrics.

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 3198 matching lines @@
       "android/web_contents_factory.cc",
       "android/web_contents_factory.h",
       "android/webapk/chrome_webapk_host.cc",
       "android/webapk/chrome_webapk_host.h",
       "android/webapk/manifest_upgrade_detector_fetcher.cc",
       "android/webapk/manifest_upgrade_detector_fetcher.h",
       "android/webapk/webapk_icon_hasher.cc",
       "android/webapk/webapk_icon_hasher.h",
       "android/webapk/webapk_installer.cc",
       "android/webapk/webapk_installer.h",
+      "android/webapk/webapk_metrics.cc",
+      "android/webapk/webapk_metrics.h",
       "android/webapk/webapk_update_manager.cc",
       "android/webapk/webapk_update_manager.h",
       "android/webapk/webapk_web_manifest_checker.cc",
       "android/webapk/webapk_web_manifest_checker.h",
       "android/webapps/add_to_homescreen_data_fetcher.cc",
       "android/webapps/add_to_homescreen_data_fetcher.h",
       "android/webapps/add_to_homescreen_manager.cc",
       "android/webapps/add_to_homescreen_manager.h",
       "android/webapps/single_tab_mode_tab_helper.cc",
       "android/webapps/single_tab_mode_tab_helper.h",
@@ skipping 1023 matching lines @@
   # linking all of the test support.
   static_library("pepper_cdm_test_constants") {
     testonly = true
     visibility = [ "//chrome/*" ]
     sources = [
       "media/pepper_cdm_test_constants.cc",
       "media/pepper_cdm_test_constants.h",
     ]
   }
 }