Re-enable DNS prefetch. This feature got disable accidentially in WebKit

webkit/glue/webpreferences.cc

 // Copyright (c) 2011 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 "webkit/glue/webpreferences.h"
 
 #include "base/string_util.h"
 #include "base/utf_string_conversions.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebRuntimeFeatures.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebKit.h"
@@ skipping 31 matching lines @@
       site_specific_quirks_enabled(false),
       shrinks_standalone_images_to_fit(true),
       uses_universal_detector(false),  // Disabled: page cycler regression
       text_areas_are_resizable(true),
       java_enabled(true),
       allow_scripts_to_close_windows(false),
       uses_page_cache(false),
       remote_fonts_enabled(true),
       javascript_can_access_clipboard(false),
       xss_auditor_enabled(false),
+      dns_prefetching_enabled(true),
       local_storage_enabled(false),
       databases_enabled(false),
       application_cache_enabled(false),
       tabs_to_links(true),
       caret_browsing_enabled(false),
       hyperlink_auditing_enabled(true),
       user_style_sheet_enabled(false),
       author_and_user_styles_enabled(true),
       frame_flattening_enabled(false),
       allow_universal_access_from_file_urls(false),
@@ skipping 51 matching lines @@
   settings->setAllowScriptsToCloseWindows(allow_scripts_to_close_windows);
   if (user_style_sheet_enabled)
     settings->setUserStyleSheetLocation(user_style_sheet_location);
   else
     settings->setUserStyleSheetLocation(WebURL());
   settings->setAuthorAndUserStylesEnabled(author_and_user_styles_enabled);
   settings->setUsesPageCache(uses_page_cache);
   settings->setDownloadableBinaryFontsEnabled(remote_fonts_enabled);
   settings->setJavaScriptCanAccessClipboard(javascript_can_access_clipboard);
   settings->setXSSAuditorEnabled(xss_auditor_enabled);
+  settings->setDNSPrefetchingEnabled(dns_prefetching_enabled);
   settings->setLocalStorageEnabled(local_storage_enabled);
   WebRuntimeFeatures::enableDatabase(
       WebRuntimeFeatures::isDatabaseEnabled() || databases_enabled);
   settings->setOfflineWebApplicationCacheEnabled(application_cache_enabled);
   settings->setCaretBrowsingEnabled(caret_browsing_enabled);
   settings->setHyperlinkAuditingEnabled(hyperlink_auditing_enabled);
 
   // This setting affects the behavior of links in an editable region:
   // clicking the link should select it rather than navigate to it.
   // Safari uses the same default. It is unlikley an embedder would want to
@@ skipping 88 matching lines @@
   // ChromeClient::tabsToLinks which is part of the glue code.
   web_view->setTabsToLinks(tabs_to_links);
 
   settings->setInteractiveFormValidationEnabled(
       interactive_form_validation_enabled);
 
   settings->setFullScreenEnabled(fullscreen_enabled);
   settings->setAllowDisplayOfInsecureContent(allow_displaying_insecure_content);
   settings->setAllowRunningOfInsecureContent(allow_running_insecure_content);
 }