Fix syncing of system theme on Linux

chrome/browser/themes/theme_service_aurax11.cc

 // Copyright 2013 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/themes/theme_service_aurax11.h"
 
 #include "base/bind.h"
 #include "base/prefs/pref_service.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/themes/custom_theme_supplier.h"
@@ skipping 64 matching lines @@
 ThemeServiceAuraX11::~ThemeServiceAuraX11() {}
 
 bool ThemeServiceAuraX11::ShouldInitWithSystemTheme() const {
   return profile()->GetPrefs()->GetBoolean(prefs::kUsesSystemTheme);
 }
 
 void ThemeServiceAuraX11::UseSystemTheme() {
   SetCustomDefaultTheme(new SystemThemeX11(profile()->GetPrefs()));
 }
 
+bool ThemeServiceAuraX11::IsSystemThemeDistinctFromDefaultTheme() const {
+  return true;
+}
+
 bool ThemeServiceAuraX11::UsingDefaultTheme() const {
   return ThemeService::UsingDefaultTheme() && !UsingSystemTheme();
 }
 
 bool ThemeServiceAuraX11::UsingSystemTheme() const {
   const CustomThemeSupplier* theme_supplier = get_theme_supplier();
   return theme_supplier &&
          theme_supplier->get_theme_type() == CustomThemeSupplier::NATIVE_X11;
 }