Introduce HistoryClient interface

components/history.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',
-      'type': 'static_library',
-      'dependencies': [
-        '../base/base.gyp:base',
-      ],
+      'target_name': 'history_core_browser',
+      'type': 'none',
       'include_dirs': [
         '..',
       ],
+      'dependencies': [
+        '../base/base.gyp:base',
+        'keyed_service_core',
+      ],
       'sources': [
-        'language_usage_metrics/language_usage_metrics.cc',
-        'language_usage_metrics/language_usage_metrics.h',
+        'history/core/browser/history_client.h',
       ],
     },
   ],
 }