Adds code for a new Aura shell.

ui/aura_shell/desktop_layout_manager.cc

Index: ui/aura_shell/desktop_layout_manager.cc
===================================================================
--- ui/aura_shell/desktop_layout_manager.cc	(revision 101422)
+++ ui/aura_shell/desktop_layout_manager.cc	(working copy)
@@ -12,7 +12,8 @@
 
 DesktopLayoutManager::DesktopLayoutManager(aura::Window* owner)
     : owner_(owner),
-      background_widget_(NULL) {
+      background_widget_(NULL),
+      launcher_widget_(NULL) {
 }
 
 DesktopLayoutManager::~DesktopLayoutManager() {
@@ -24,4 +25,11 @@
 void DesktopLayoutManager::OnWindowResized() {
   background_widget_->SetBounds(
       gfx::Rect(owner_->bounds().width(), owner_->bounds().height()));
+
+  gfx::Rect launcher_bounds = launcher_widget_->GetWindowScreenBounds();
+  launcher_widget_->SetBounds(
+      gfx::Rect(owner_->bounds().width() / 2 - launcher_bounds.width() / 2,
+                owner_->bounds().bottom() - launcher_bounds.height(),
+                launcher_bounds.width(),
+                launcher_bounds.height()));
 }