Adds code for a new Aura shell.

ui/aura_shell/desktop_layout_manager.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 "ui/aura_shell/desktop_layout_manager.h"
+
+#include "ui/aura/window.h"
+#include "views/widget/widget.h"
+
+////////////////////////////////////////////////////////////////////////////////
+// DesktopLayoutManager, public:
+
+DesktopLayoutManager::DesktopLayoutManager(aura::Window* owner)
+    : owner_(owner),
+      background_widget_(NULL) {
+}
+
+DesktopLayoutManager::~DesktopLayoutManager() {
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// DesktopLayoutManager, aura::LayoutManager implementation:
+
+void DesktopLayoutManager::OnWindowResized() {
+  background_widget_->SetBounds(
+      gfx::Rect(owner_->bounds().width(), owner_->bounds().height()));
+}