Turn on better popup blocker by default.

chrome/browser/ui/browser.cc

 // Copyright 2012 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/browser.h"
 
 #if defined(OS_WIN)
 #include <windows.h>
 #include <shellapi.h>
 #endif  // defined(OS_WIN)
@@ skipping 1262 matching lines @@
   FillNavigateParamsFromOpenURLParams(&nav_params, params);
   nav_params.source_contents = source;
   nav_params.tabstrip_add_types = TabStripModel::ADD_NONE;
   nav_params.window_action = chrome::NavigateParams::SHOW_WINDOW;
   nav_params.user_gesture = params.user_gesture;
 
   PopupBlockerTabHelper* popup_blocker_helper = NULL;
   if (source)
     popup_blocker_helper = PopupBlockerTabHelper::FromWebContents(source);
 
-  if (CommandLine::ForCurrentProcess()->HasSwitch(
-          switches::kEnableBetterPopupBlocking) &&
+  if (!CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kDisableBetterPopupBlocking) &&
       popup_blocker_helper) {
 
     if ((params.disposition == NEW_POPUP ||
          params.disposition == NEW_FOREGROUND_TAB ||
          params.disposition == NEW_BACKGROUND_TAB) &&
         !params.user_gesture && !CommandLine::ForCurrentProcess()->HasSwitch(
                                     switches::kDisablePopupBlocking)) {
       if (popup_blocker_helper->MaybeBlockPopup(nav_params,
                                                 WebWindowFeatures())) {
         return NULL;
@@ skipping 198 matching lines @@
     WindowOpenDisposition disposition,
     const WebWindowFeatures& features,
     bool user_gesture,
     bool opener_suppressed) {
   if (window_container_type == WINDOW_CONTAINER_TYPE_BACKGROUND) {
     // If a BackgroundContents is created, suppress the normal WebContents.
     return !MaybeCreateBackgroundContents(
         route_id, web_contents, frame_name, target_url);
   }
 
-  if (!CommandLine::ForCurrentProcess()->HasSwitch(
-          switches::kEnableBetterPopupBlocking)) {
+  if (CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kDisableBetterPopupBlocking)) {
     return true;
   }
 
   PopupBlockerTabHelper* popup_blocker_helper =
       PopupBlockerTabHelper::FromWebContents(web_contents);
   if (!popup_blocker_helper)
     return true;
 
   if ((disposition == NEW_POPUP || disposition == NEW_FOREGROUND_TAB ||
        disposition == NEW_BACKGROUND_TAB) && !user_gesture &&
@@ skipping 771 matching lines @@
   if (contents && !allow_js_access) {
     contents->web_contents()->GetController().LoadURL(
         target_url,
         content::Referrer(),
         content::PAGE_TRANSITION_LINK,
         std::string());  // No extra headers.
   }
 
   return contents != NULL;
 }