Introduce proximity_auth component.

components/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.
 
 # Collection of all components. You wouldn't link to this, but this is rather
 # to reference the files so they can be compiled by the build system.
 group("all_components") {
   visibility = "//:*"  # Only for the root targets to bring in.
 
   deps = [
@@ skipping 44 matching lines @@
     "//components/pairing",
     "//components/password_manager/content/browser",
     "//components/password_manager/core/browser",
     "//components/password_manager/core/common",
     "//components/plugins/renderer",
     "//components/policy",
     "//components/power",
     "//components/precache/core",
     "//components/precache/content",
     "//components/pref_registry",
+    "//components/proximity_auth",
     "//components/query_parser",
     "//components/rappor",
     "//components/resources:components_resources",
     "//components/search",
     "//components/search_engines",
     "//components/search_provider_logos",
     "//components/sessions",
     "//components/signin/core/browser",
     "//components/startup_metric_utils",
     "//components/strings",
@@ skipping 124 matching lines @@
   ]
 
   # TODO(GYP) need this target.
   #'breakpad/app/crash_keys_win_unittest.cc',
 
   # Precache tests need these defines.
   #configs += [ "//components/precache/core:precache_config" ]
 }
 
 }