Use gyp targets to link in X11 libraries instead of setting -lXfoo

ui/aura/aura.gyp

 # Copyright (c) 2012 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': [
     {
@@ skipping 102 matching lines @@
         'window_layer_type.h',
         'window_observer.h',
         'window_tracker.cc',
         'window_tracker.h',
         'window_tree_host.cc',
         'window_tree_host.h',
         'window_tree_host_delegate.h',
       ],
       'conditions': [
         ['use_x11==1', {
-          'link_settings': {
-            'libraries': [
-              '-lX11',
-              '-lXi',
-              '-lXfixes',
-              '-lXrandr',
-            ],
-          },
+          'dependencies': [
+            '../../build/linux/system.gyp:x11',
+            '../../build/linux/system.gyp:xfixes',
+            '../../build/linux/system.gyp:xrandr',
+            '../../build/linux/system.gyp:xi',
+          ],
         }],
         ['OS=="win"', {
           'dependencies': [
             '../metro_viewer/metro_viewer.gyp:metro_viewer_messages',
             '../../ipc/ipc.gyp:ipc',
           ],
           'sources!': [
             'input_state_lookup.cc',
           ],
         }],
@@ skipping 145 matching lines @@
         ['OS=="linux" and linux_use_tcmalloc==1', {
           'dependencies': [
            # See http://crbug.com/162998#c4 for why this is needed.
             '../../base/allocator/allocator.gyp:allocator',
           ],
         }],
       ],
     },
   ],
 }