MD Settings: allow changing to GTK+ theme on Linux

chrome/browser/ui/webui/settings/md_settings_localized_strings_provider.cc

 // 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.
 
 #include "chrome/browser/ui/webui/settings/md_settings_localized_strings_provider.h"
 
 #include <string>
 
 #include "base/command_line.h"
 #include "base/i18n/number_formatting.h"
@@ skipping 236 matching lines @@
   base::DictionaryValue localized_values;
   chromeos::AddAccountUITweaksLocalizedValues(&localized_values, profile);
   html_source->AddLocalizedStrings(localized_values);
 }
 #endif
 
 void AddAppearanceStrings(content::WebUIDataSource* html_source) {
   LocalizedString localized_strings[] = {
     {"appearancePageTitle", IDS_SETTINGS_APPEARANCE},
     {"exampleDotCom", IDS_SETTINGS_EXAMPLE_DOT_COM},
-    {"theme", IDS_SETTINGS_THEME},
+    {"themes", IDS_SETTINGS_THEMES},
+#if defined(OS_LINUX) && !defined(OS_CHROMEOS)
+    {"systemTheme", IDS_SETTINGS_SYSTEM_THEME},
+    {"useSystemTheme", IDS_SETTINGS_USE_SYSTEM_THEME},
+    {"classicTheme", IDS_SETTINGS_CLASSIC_THEME},
+    {"useClassicTheme", IDS_SETTINGS_USE_CLASSIC_THEME},
+#else
     {"resetToDefaultTheme", IDS_SETTINGS_RESET_TO_DEFAULT_THEME},
+#endif
     {"showHomeButton", IDS_SETTINGS_SHOW_HOME_BUTTON},
     {"showBookmarksBar", IDS_SETTINGS_SHOW_BOOKMARKS_BAR},
     {"homePageNtp", IDS_SETTINGS_HOME_PAGE_NTP},
     {"other", IDS_SETTINGS_OTHER},
     {"changeHomePage", IDS_SETTINGS_CHANGE_HOME_PAGE},
     {"themesGalleryUrl", IDS_THEMES_GALLERY_URL},
     {"chooseFromWebStore", IDS_SETTINGS_WEB_STORE},
     {"chooseFonts", IDS_SETTINGS_CHOOSE_FONTS},
 #if defined(OS_CHROMEOS)
     {"openWallpaperApp", IDS_SETTINGS_OPEN_WALLPAPER_APP},
@@ skipping 1442 matching lines @@
 #endif
   AddUsersStrings(html_source);
   AddWebContentStrings(html_source);
 
   policy_indicator::AddLocalizedStrings(html_source);
 
   html_source->SetJsonPath(kLocalizedStringsFile);
 }
 
 }  // namespace settings