Create component to expose network usage stats to consumers.

components/data_usage.gypi

 # Copyright 2015 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': [
     {
-      # GN version: //components/toolbar
-      'target_name': 'toolbar',
+      'target_name': 'data_usage_core',
       'type': 'static_library',
       'dependencies': [
         '../base/base.gyp:base',
+        '../net/net.gyp:net',
         '../url/url.gyp:url_lib',
       ],
-      'include_dirs': [
-        '..',
-      ],
       'sources': [
-        # Note: sources list duplicated in GN build.
-        'toolbar/toolbar_model.cc',
-        'toolbar/toolbar_model.h',
-      ],
+        'data_usage/core/data_use.cc',
+        'data_usage/core/data_use.h',
+        'data_usage/core/data_use_aggregator.cc',
+        'data_usage/core/data_use_aggregator.h',
+      ]
     },
-  ],
+  ]
 }