MD Settings: Fix subpage visibility and add appearance page tests

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

Index: chrome/test/data/webui/settings/cr_settings_browsertest.js
diff --git a/chrome/test/data/webui/settings/cr_settings_browsertest.js b/chrome/test/data/webui/settings/cr_settings_browsertest.js
index 376938e9c2bbe8b5f2d31ed5ae9ce9c0b7437368..3c50e92aece6a07c2f67cc6ca08ea67cef15d2f9 100644
--- a/chrome/test/data/webui/settings/cr_settings_browsertest.js
+++ b/chrome/test/data/webui/settings/cr_settings_browsertest.js
@@ -1219,10 +1219,7 @@ TEST_F('CrSettingsRouteDynamicParametersTest', 'All', function() {
   mocha.run();
 });
 
-// Times out on Windows Tests (dbg). See https://crbug.com/651296.
-// Times out / crashes on chromium.linux/Linux Tests (dbg) crbug.com/667882
-GEN('#if defined(OS_WIN) || defined(OS_CHROMEOS) || defined(OS_LINUX)' +
-    ' || defined(OS_MACOSX)');
+GEN('#if !defined(NDEBUG)');
 GEN('#define MAYBE_MainPage_All DISABLED_All');
 GEN('#else');
 GEN('#define MAYBE_MainPage_All All');
@@ -1243,13 +1240,14 @@ CrSettingsMainPageTest.prototype = {
 
   /** @override */
   extraLibraries: CrSettingsBrowserTest.prototype.extraLibraries.concat([
+    '../fake_chrome_event.js',
+    'fake_settings_private.js',
     'test_browser_proxy.js',
     'settings_main_test.js',
   ]),
 };
 
 TEST_F('CrSettingsMainPageTest', 'MAYBE_MainPage_All', function() {
-  settings_main_page.registerTests();
   mocha.run();
 });