Basic UkmService implementation

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 1481 matching lines @@
     "//components/sync",
     "//components/sync_bookmarks",
     "//components/sync_preferences",
     "//components/sync_sessions",
     "//components/task_scheduler_util/browser",
     "//components/task_scheduler_util/common",
     "//components/tracing:startup_tracing",
     "//components/translate/content/browser",
     "//components/translate/core/browser",
     "//components/translate/core/common",
+    "//components/ukm:observers",
     "//components/undo",
     "//components/update_client",
     "//components/upload_list",
     "//components/url_formatter",
     "//components/url_matcher",
     "//components/user_prefs",
     "//components/user_prefs/tracked:user_prefs_tracked",
     "//components/variations",
     "//components/variations/field_trial_config",
     "//components/variations/net",
@@ skipping 2974 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"
 }