Re-implement the screensaver to use WebView instead of ExtensionDialogHost.

ash/shell/shell_delegate_impl.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 "ash/shell/shell_delegate_impl.h"
 
 #include "ash/shell/example_factory.h"
 #include "ash/shell/launcher_delegate_impl.h"
 #include "ash/shell/toplevel_window.h"
 #include "ash/shell_window_ids.h"
@@ skipping 57 matching lines @@
 
 void ShellDelegateImpl::OpenFileManager() {
 }
 
 void ShellDelegateImpl::OpenCrosh() {
 }
 
 void ShellDelegateImpl::OpenMobileSetup() {
 }
 
+content::BrowserContext* ShellDelegateImpl::GetCurrentBrowserContext() {
+  return Shell::GetInstance()->browser_context();
+}
+
 ash::AppListViewDelegate* ShellDelegateImpl::CreateAppListViewDelegate() {
   return ash::shell::CreateAppListViewDelegate();
 }
 
 void ShellDelegateImpl::StartPartialScreenshot(
     ash::ScreenshotDelegate* screenshot_delegate) {
   ash::PartialScreenshotView::StartPartialScreenshot(screenshot_delegate);
 }
 
 ash::LauncherDelegate* ShellDelegateImpl::CreateLauncherDelegate(
     ash::LauncherModel* model) {
   launcher_delegate_ = new LauncherDelegateImpl(watcher_);
   return launcher_delegate_;
 }
 
 ash::SystemTrayDelegate* ShellDelegateImpl::CreateSystemTrayDelegate(
     ash::SystemTray* tray) {
   return NULL;
 }
 
 ash::UserWallpaperDelegate* ShellDelegateImpl::CreateUserWallpaperDelegate() {
   return NULL;
 }
 
 }  // namespace shell
 }  // namespace ash