Fix remoting_unittests compilation with Aura

remoting/remoting.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': {
     # TODO(dmaclach): can we pick this up some other way? Right now it's
     # duplicated from chrome.gyp
     'chromium_code': 1,
     # Use consistent strings across all platforms. Note that the plugin name
@@ skipping 1172 matching lines @@
             ],
           },
         }],
         ['toolkit_uses_gtk==1', {
           'dependencies': [
             '../build/linux/system.gyp:gtk',
           ],
         }, {  # else toolkit_uses_gtk!=1
           'sources!': [
             '*_gtk.cc',
+          ],
+        }],
+        ['OS!="linux"', {
+          'sources!': [
             'host/x_server_pixel_buffer.cc',
             'host/x_server_pixel_buffer.h',
           ],
         }],
         ['OS=="mac"', {
           'sources': [
             '../third_party/GTM/AppKit/GTMCarbonEvent.h',
             '../third_party/GTM/AppKit/GTMCarbonEvent.m',
             '../third_party/GTM/DebugUtils/GTMDebugSelectorValidation.h',
             '../third_party/GTM/DebugUtils/GTMTypeCasting.h',
@@ skipping 513 matching lines @@
                   '../base/allocator/allocator.gyp:allocator',
                 ],
               },
             ],
           ],
         }],
       ],  # end of 'conditions'
     },  # end of target 'remoting_unittests'
   ],  # end of targets
 }