[WebUI] Disable 3 flaky tests on ChromiumOS dbg (timeouts)

chrome/test/data/webui/settings/settings_subpage_browsertest.js

 // Copyright 2015 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.
 
 /**
  * @fileoverview Suite of tests to ensure that settings subpages exist and
  * load without errors. Also outputs approximate load times for each subpage.
  */
 
 GEN_INCLUDE(['settings_page_browsertest.js']);
@@ skipping 78 matching lines @@
   if (cr.isChromeOS)
     this.subPages.push('internet', 'bluetooth', 'device');
   else
     this.subPages.push('defaultBrowser');
 }
 
 SettingsBasicSubPageBrowserTest.prototype = {
   __proto__: SettingsSubPageBrowserTest.prototype,
 };
 
-TEST_F('SettingsBasicSubPageBrowserTest', 'SubPages', function() {
+// Failing on ChromiumOS dbg. https://crbug.com/709442
+GEN('#if defined(OS_CHROMEOS) && !defined(NDEBUG)');
+GEN('#define MAYBE_SubPages DISABLED_SubPages');
+GEN('#else');
+GEN('#define MAYBE_SubPages SubPages');
+GEN('#endif');
+TEST_F('SettingsBasicSubPageBrowserTest', 'MAYBE_SubPages', function() {
   suiteSetup(this.verifySubPagesHidden_.bind(this));
   suite('Basic', this.testSubPages.bind(this));
   mocha.run();
 });
 
 /** @constructor @extends {SettingsSubPageBrowserTest} */
 function SettingsAdvancedSubPageBrowserTest() {
   // "Advanced" sections live in the settings-basic-page.
   SettingsSubPageBrowserTest.call(this, 'basic');
 
@@ skipping 21 matching lines @@
     this.toggleAdvanced();
     SettingsSubPageBrowserTest.prototype.setUp.call(this);
   },
 };
 
 TEST_F('SettingsAdvancedSubPageBrowserTest', 'SubPages', function() {
   suiteSetup(this.verifySubPagesHidden_.bind(this));
   suite('Advanced', this.testSubPages.bind(this));
   mocha.run();
 });