Clean up how we handle themes in the extensions system and management API....

chrome/browser/extensions/theme_installed_infobar_delegate.cc

 // Copyright (c) 2011 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 <string>
 
 #include "base/utf_string_conversions.h"
 #include "chrome/browser/extensions/extension_service.h"
@@ skipping 33 matching lines @@
   profile_->GetThemeProvider()->OnInfobarDestroyed();
 }
 
 bool ThemeInstalledInfoBarDelegate::Cancel() {
   if (!previous_theme_id_.empty()) {
     ExtensionService* service = profile_->GetExtensionService();
     if (service) {
       const Extension* previous_theme =
           service->GetExtensionById(previous_theme_id_, true);
       if (previous_theme) {
-        profile_->SetTheme(previous_theme);
+        service->EnableExtension(previous_theme_id_);
         return true;
       }
     }
   }
 
   profile_->ClearTheme();
   return true;
 }
 
 void ThemeInstalledInfoBarDelegate::InfoBarClosed() {
@@ skipping 44 matching lines @@
       tab_contents_ = NULL;
       // Although it's not being used anymore, this delegate is never deleted.
       // It can not be deleted now because it is still needed if we
       // "undo" the theme change that triggered this notification
       // (when InfoBar::OnBackgroundExpose() is called). This will likely
       // be fixed when infobar delegate deletion is cleaned up for
       // http://crbug.com/62154.
     }
   }
 }