Move enable extensions define to a build flag.

chrome/browser/sessions/session_tab_helper.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/sessions/session_tab_helper.h"
 
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/sessions/session_service.h"
 #include "chrome/browser/sessions/session_service_factory.h"
 #include "chrome/common/features.h"
 #include "content/public/browser/web_contents.h"
+#include "extensions/features/features.h"
 
-#if defined(ENABLE_EXTENSIONS)
+#if BUILDFLAG(ENABLE_EXTENSIONS)
 #include "extensions/common/extension_messages.h"
 #endif
 
 DEFINE_WEB_CONTENTS_USER_DATA_KEY(SessionTabHelper);
 
 SessionTabHelper::SessionTabHelper(content::WebContents* contents)
     : content::WebContentsObserver(contents) {
 }
 
 SessionTabHelper::~SessionTabHelper() {
 }
 
 void SessionTabHelper::SetWindowID(const SessionID& id) {
   window_id_ = id;
 
-#if defined(ENABLE_EXTENSIONS)
+#if BUILDFLAG(ENABLE_EXTENSIONS)
   // Extension code in the renderer holds the ID of the window that hosts it.
   // Notify it that the window ID changed.
   web_contents()->SendToAllFrames(
       new ExtensionMsg_UpdateBrowserWindowId(MSG_ROUTING_NONE, id.id()));
 #endif
 }
 
 // static
 SessionID::id_type SessionTabHelper::IdForTab(const content::WebContents* tab) {
   const SessionTabHelper* session_tab_helper =
@@ skipping 11 matching lines @@
 
 void SessionTabHelper::UserAgentOverrideSet(const std::string& user_agent) {
 #if BUILDFLAG(ENABLE_SESSION_SERVICE)
   Profile* profile =
       Profile::FromBrowserContext(web_contents()->GetBrowserContext());
   SessionService* session = SessionServiceFactory::GetForProfile(profile);
   if (session)
     session->SetTabUserAgentOverride(window_id(), session_id(), user_agent);
 #endif
 }