Fix user agent override restore pipeline

chrome/browser/ui/tab_contents/tab_contents.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/ui/tab_contents/tab_contents.h"
 
 #include "base/command_line.h"
 #include "base/lazy_instance.h"
 #include "chrome/browser/autofill/autocomplete_history_manager.h"
 #include "chrome/browser/autofill/autofill_external_delegate.h"
@@ skipping 10 matching lines @@
 #include "chrome/browser/net/cache_stats.h"
 #include "chrome/browser/omnibox_search_hint.h"
 #include "chrome/browser/password_manager/password_manager.h"
 #include "chrome/browser/password_manager/password_manager_delegate_impl.h"
 #include "chrome/browser/plugin_observer.h"
 #include "chrome/browser/prerender/prerender_tab_helper.h"
 #include "chrome/browser/printing/print_preview_message_handler.h"
 #include "chrome/browser/printing/print_view_manager.h"
 #include "chrome/browser/safe_browsing/safe_browsing_tab_observer.h"
 #include "chrome/browser/sessions/restore_tab_helper.h"
+#include "chrome/browser/sessions/session_service.h"
+#include "chrome/browser/sessions/session_service_factory.h"
 #include "chrome/browser/tab_contents/navigation_metrics_recorder.h"
 #include "chrome/browser/tab_contents/tab_contents_ssl_helper.h"
 #include "chrome/browser/tab_contents/thumbnail_generator.h"
 #include "chrome/browser/translate/translate_tab_helper.h"
 #include "chrome/browser/ui/alternate_error_tab_observer.h"
 #include "chrome/browser/ui/blocked_content/blocked_content_tab_helper.h"
 #include "chrome/browser/ui/bookmarks/bookmark_tab_helper.h"
 #include "chrome/browser/ui/constrained_window_tab_helper.h"
 #include "chrome/browser/ui/find_bar/find_tab_helper.h"
 #include "chrome/browser/ui/hung_plugin_tab_helper.h"
@@ skipping 203 matching lines @@
 
 ////////////////////////////////////////////////////////////////////////////////
 // WebContentsObserver overrides
 
 void TabContents::WebContentsDestroyed(WebContents* tab) {
   // Destruction of the WebContents should only be done by us from our
   // destructor. Otherwise it's very likely we (or one of the helpers we own)
   // will attempt to access the WebContents and we'll crash.
   DCHECK(in_destructor_);
 }
+
+void TabContents::SetUserAgentOverride(const std::string& user_agent) {
+#if defined(ENABLE_SESSION_SERVICE)
+  SessionService* session =
+      SessionServiceFactory::GetForProfile(profile());
+  if (session) {
+    session->SetTabUserAgentOverride(restore_tab_helper()->window_id(),
+                                     restore_tab_helper()->session_id(),
+                                     user_agent);
+  }
+#endif
+}