Reverting this as it breaks (at least) the Windows Aura build.

chrome/browser/ui/views/aura/chrome_shell_delegate.cc

Index: chrome/browser/ui/views/aura/chrome_shell_delegate.cc
===================================================================
--- chrome/browser/ui/views/aura/chrome_shell_delegate.cc	(revision 110804)
+++ chrome/browser/ui/views/aura/chrome_shell_delegate.cc	(working copy)
@@ -12,22 +12,12 @@
 #include "ui/aura/window.h"
 #include "ui/aura_shell/launcher/launcher_types.h"
 
-// static
-ChromeShellDelegate* ChromeShellDelegate::instance_ = NULL;
-
 ChromeShellDelegate::ChromeShellDelegate() {
-  instance_ = this;
 }
 
 ChromeShellDelegate::~ChromeShellDelegate() {
-  if (instance_ == this)
-    instance_ = NULL;
 }
 
-const views::View* ChromeShellDelegate::GetStatusArea() const {
-  return status_area_host_->GetStatusArea();
-}
-
 // static
 bool ChromeShellDelegate::ShouldCreateLauncherItemForBrowser(
     Browser* browser,