Move enable extensions define to a build flag.

chrome/browser/tab_contents/tab_util.cc

 // Copyright (c) 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/tab_contents/tab_util.h"
 
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/webui/chrome_web_ui_controller_factory.h"
 #include "chrome/common/chrome_switches.h"
 #include "content/public/browser/render_frame_host.h"
 #include "content/public/browser/render_view_host.h"
 #include "content/public/browser/site_instance.h"
 #include "content/public/browser/web_contents.h"
+#include "extensions/features/features.h"
 #include "url/gurl.h"
 
-#if defined(ENABLE_EXTENSIONS)
+#if BUILDFLAG(ENABLE_EXTENSIONS)
 #include "extensions/browser/extension_registry.h"
 #endif
 
 using content::RenderFrameHost;
 using content::RenderViewHost;
 using content::SiteInstance;
 using content::WebContents;
 
 namespace tab_util {
 
@@ skipping 15 matching lines @@
   return WebContents::FromRenderFrameHost(render_frame_host);
 }
 
 scoped_refptr<SiteInstance> GetSiteInstanceForNewTab(Profile* profile,
                                                      const GURL& url) {
   // If |url| is a WebUI or extension, we set the SiteInstance up front so that
   // we don't end up with an extra process swap on the first navigation.
   if (ChromeWebUIControllerFactory::GetInstance()->UseWebUIForURL(profile, url))
     return SiteInstance::CreateForURL(profile, url);
 
-#if defined(ENABLE_EXTENSIONS)
+#if BUILDFLAG(ENABLE_EXTENSIONS)
    if (extensions::ExtensionRegistry::Get(
        profile)->enabled_extensions().GetHostedAppByURL(url))
      return SiteInstance::CreateForURL(profile, url);
 #endif
 
   // We used to share the SiteInstance for same-site links opened in new tabs,
   // to leverage the in-memory cache and reduce process creation.  It now
   // appears that it is more useful to have such links open in a new process,
   // so we create new tabs in a new BrowsingInstance.
    return nullptr;
 }
 
 }  // namespace tab_util