Unpack theme data from extensions off of UI thread.

chrome/browser/extensions/theme_installed_infobar_delegate.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/extensions/theme_installed_infobar_delegate.h"
 
 #include <stddef.h>
 #include <string>
 #include <utility>
 
@@ skipping 126 matching lines @@
     InfoBarButton button) const {
   DCHECK_EQ(BUTTON_CANCEL, button);
   return l10n_util::GetStringUTF16(IDS_THEME_INSTALL_INFOBAR_UNDO_BUTTON);
 }
 
 bool ThemeInstalledInfoBarDelegate::Cancel() {
   if (!previous_theme_id_.empty()) {
     const extensions::Extension* previous_theme =
         extension_service_->GetExtensionById(previous_theme_id_, true);
     if (previous_theme) {
-      theme_service_->SetTheme(previous_theme);
+      theme_service_->RevertToTheme(previous_theme);
+      // TODO(estade): while we're waiting to close, it would be nice to
+      // indicate that the theme is busy reverting.
       return false;  // The theme change will close us.
     }
   }
 
   if (previous_using_system_theme_)
     theme_service_->UseSystemTheme();
   else
     theme_service_->UseDefaultTheme();
   return false;  // The theme change will close us.
 }
 
 void ThemeInstalledInfoBarDelegate::Observe(
     int type,
     const content::NotificationSource& source,
     const content::NotificationDetails& details) {
   DCHECK_EQ(chrome::NOTIFICATION_BROWSER_THEME_CHANGED, type);
   // If the new theme is different from what this info bar is associated with,
   // close this info bar since it is no longer relevant.
   if (theme_id_ != theme_service_->GetThemeID())
     infobar()->RemoveSelf();
 }