[Athena] minimum impl to add screen/background and test windows

athena/athena.gyp

+# 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.
+
+{
+  'variables': {
+    'chromium_code': 1,
+  },
+  'targets': [
+    {
+      'target_name': 'athena_lib',
+      'type': '<(component)',
+      'dependencies': [
+        '../ui/aura/aura.gyp:aura',
+        '../ui/views/views.gyp:views',
+        '../ui/accessibility/accessibility.gyp:ax_gen',
+        '../skia/skia.gyp:skia',
+      ],
+      'defines': [
+        'ATHENA_IMPLEMENTATION',
+      ],
+      'sources': [
+        # All .cc, .h under athena, except unittests
+        'athena_export.h',
+        'screen/background_controller.h',
+        'screen/background_controller.cc',
+        'screen/public/screen_manager.h',
+        'screen/screen_manager_impl.cc',
+        'wm/public/window_manager.h',
+        'wm/window_manager_impl.cc',
+      ],
+    },
+  ],
+}
+