Introduce proximity_auth component.

components/proximity_auth.gypi

 # 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.
 
 {
   'targets': [
     {
-      'target_name': 'language_usage_metrics',
+      'target_name': 'proximity_auth',
       'type': 'static_library',
+      'include_dirs': [
+        '..',
+      ],
       'dependencies': [
         '../base/base.gyp:base',
       ],
-      'include_dirs': [
-        '..',
-      ],
       'sources': [
-        'language_usage_metrics/language_usage_metrics.cc',
-        'language_usage_metrics/language_usage_metrics.h',
+        "proximity_auth/proximity_auth_system.cc",
+        "proximity_auth/proximity_auth_system.h",
+        "proximity_auth/remote_device.h",
       ],
     },
   ],
 }