Remove the singleton instance get/delete methods from RootWindow (yay)

ash/shell.cc

Index: ash/shell.cc
===================================================================
--- ash/shell.cc	(revision 124527)
+++ ash/shell.cc	(working copy)
@@ -270,11 +270,7 @@
 // Shell, public:
 
 Shell::Shell(ShellDelegate* delegate)
-    : root_filter_(new internal::RootWindowEventFilter),
-#if !defined(OS_MACOSX)
-      nested_dispatcher_controller_(new NestedDispatcherController),
-      accelerator_controller_(new AcceleratorController),
-#endif
+    : root_window_(new aura::RootWindow),
       delegate_(delegate),
       audio_controller_(NULL),
       brightness_controller_(NULL),
@@ -283,8 +279,6 @@
       desktop_background_mode_(BACKGROUND_IMAGE),
       root_window_layout_(NULL),
       status_widget_(NULL) {
-  // Pass ownership of the filter to the root window.
-  GetRootWindow()->SetEventFilter(root_filter_);
 }
 
 Shell::~Shell() {
@@ -320,7 +314,10 @@
 
   // These need a valid Shell instance to clean up properly, so explicitly
   // delete them before invalidating the instance.
+  // Alphabetical.
+  activation_controller_.reset();
   drag_drop_controller_.reset();
+  shadow_controller_.reset();
   window_cycle_controller_.reset();
 
   // Launcher widget has a InputMethodBridge that references to
@@ -356,10 +353,18 @@
 
 // static
 aura::RootWindow* Shell::GetRootWindow() {
-  return aura::RootWindow::GetInstance();
+  return GetInstance()->root_window_.get();
 }
 
 void Shell::Init() {
+  root_filter_ = new internal::RootWindowEventFilter;
+#if !defined(OS_MACOSX)
+  nested_dispatcher_controller_.reset(new NestedDispatcherController);
+  accelerator_controller_.reset(new AcceleratorController);
+#endif
+  // Pass ownership of the filter to the root window.
+  GetRootWindow()->SetEventFilter(root_filter_);
+
   DCHECK(!GetRootWindowEventFilterCount());
 
   // PartialScreenshotEventFilter must be the first one to capture key