Switch guest profile from forced-incognito to UI mods like ChromeOS.

chrome/browser/ui/toolbar/wrench_menu_model.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/toolbar/wrench_menu_model.h"
 
 #include <algorithm>
 #include <cmath>
 
 #include "base/command_line.h"
@@ skipping 462 matching lines @@
   if (browser_->profile()->IsManaged())
     return false;
 
 #if defined(OS_WIN)
   if (win8::IsSingleWindowMetroMode() &&
       browser_->profile()->HasOffTheRecordProfile()) {
     return false;
   }
 #endif
 
-#if defined(OS_CHROMEOS)
-  if (CommandLine::ForCurrentProcess()->HasSwitch(
-      chromeos::switches::kGuestSession)) {
-    return false;
-  }
-#endif
-
-  return true;
+  return !browser_->profile()->IsGuestSession();
 }
 
 bool WrenchMenuModel::ShouldShowNewWindowMenuItem() {
 #if defined(OS_WIN)
   if (!win8::IsSingleWindowMetroMode())
     return true;
 
   // In Win8's single window Metro mode, we only show the New Window options
   // if there isn't already a window of the requested type (incognito or not)
   // that is available.
@@ skipping 282 matching lines @@
             &enable_increment, &enable_decrement);
   }
   zoom_label_ = l10n_util::GetStringFUTF16(
       IDS_ZOOM_PERCENT, base::IntToString16(zoom_percent));
 }
 
 void WrenchMenuModel::OnZoomLevelChanged(
     const content::HostZoomMap::ZoomLevelChange& change) {
   UpdateZoomControls();
 }