Fix ChromeOS Ozone build since it doesn't have xdisplaycheck.

content/content_browsertests.isolate

 # Copyright (c) 2013 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.
 {
   'conditions': [
     ['OS=="android"', {
       'variables': {
         'isolate_dependency_tracked': [
           '<(PRODUCT_DIR)/content_shell/assets/content_shell.pak',
         ],
@@ skipping 29 matching lines @@
           '<(PRODUCT_DIR)',
           '<(PRODUCT_DIR)/content_browsertests<(EXECUTABLE_SUFFIX)',
           '--test-launcher-bot-mode',
         ],
         'isolate_dependency_tracked': [
           '../testing/xvfb.py',
           '<(PRODUCT_DIR)/content_shell.pak',
           '<(PRODUCT_DIR)/libffmpegsumo.so',
           '<(PRODUCT_DIR)/libosmesa.so',
           '<(PRODUCT_DIR)/libppapi_tests.so',
+        ],
+      },
+    }],
+    ['OS=="linux" and use_ozone==0', {
+      'variables': {
+        'isolate_dependency_tracked': [
           '<(PRODUCT_DIR)/xdisplaycheck<(EXECUTABLE_SUFFIX)',
         ],
       },
     }],
     ['OS=="linux" or OS=="mac" or OS=="win"', {
       'variables': {
         'isolate_dependency_tracked': [
           '../ppapi/tests/test_case.html',
           '../ppapi/tests/test_page.css',
           '../testing/test_env.py',
@@ skipping 46 matching lines @@
         'isolate_dependency_untracked': [
           '<(PRODUCT_DIR)/content_browsertests.exe.pdb',
         ],
       },
     }],
   ],
   'includes': [
     '../third_party/icu/icu.isolate',
   ],
 }