Rationalize linux vs x11 in ui

build/common.gypi

 # 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.
 
 # IMPORTANT:
 # Please don't directly include this file if you are building via gyp_chromium,
 # since gyp_chromium is automatically forcing its inclusion.
 {
   # Variables expected to be overriden on the GYP command line (-D) or by
   # ~/.gyp/include.gypi.
@@ skipping 117 matching lines @@
 
         'conditions': [
           # Set default value of toolkit_views based on OS.
           ['OS=="win" or chromeos==1 or use_aura==1', {
             'toolkit_views%': 1,
           }, {
             'toolkit_views%': 0,
           }],
 
           # Set toolkit_uses_gtk for the Chromium browser on Linux.
-          ['(OS=="linux" or OS=="freebsd" or OS=="openbsd" or OS=="solaris") and use_aura==0', {
+          ['(OS=="linux" or OS=="freebsd" or OS=="openbsd" or OS=="solaris") and use_aura==0 and use_messagepump_linux==0', {
             'toolkit_uses_gtk%': 1,
           }, {
             'toolkit_uses_gtk%': 0,
           }],
 
           # Enable HiDPI on Mac OS and Chrome OS.
           ['OS=="mac" or chromeos==1', {
             'enable_hidpi%': 1,
           }],
 
@@ skipping 1690 matching lines @@
       }],
       ['use_default_render_theme==1', {
         'defines': ['USE_DEFAULT_RENDER_THEME=1'],
       }],
       ['use_libjpeg_turbo==1', {
         'defines': ['USE_LIBJPEG_TURBO=1'],
       }],
       ['use_nss==1', {
         'defines': ['USE_NSS=1'],
       }],
+      ['use_x11==1', {
+        'defines': ['USE_X11=1'],
+      }],
       ['enable_one_click_signin==1', {
         'defines': ['ENABLE_ONE_CLICK_SIGNIN'],
       }],
       ['toolkit_uses_gtk==1 and toolkit_views==0', {
         # TODO(erg): We are progressively sealing up use of deprecated features
         # in gtk in preparation for an eventual porting to gtk3.
         'defines': ['GTK_DISABLE_SINGLE_INCLUDES=1'],
       }],
       ['chromeos==1', {
         'defines': ['OS_CHROMEOS=1'],
@@ skipping 2501 matching lines @@
     # settings in target dicts.  SYMROOT is a special case, because many other
     # Xcode variables depend on it, including variables such as
     # PROJECT_DERIVED_FILE_DIR.  When a source group corresponding to something
     # like PROJECT_DERIVED_FILE_DIR is added to a project, in order for the
     # files to appear (when present) in the UI as actual files and not red
     # red "missing file" proxies, the correct path to PROJECT_DERIVED_FILE_DIR,
     # and therefore SYMROOT, needs to be set at the project level.
     'SYMROOT': '<(DEPTH)/xcodebuild',
   },
 }