Eliminate Shell::RootWindowList in favor of aura::Window::Windows.

ash/touch/touch_hud_debug.cc

Index: ash/touch/touch_hud_debug.cc
diff --git a/ash/touch/touch_hud_debug.cc b/ash/touch/touch_hud_debug.cc
index 921c31c65344da8785cd4920874ba4d08b4bc395..019779d34471d3743ba95272cde0587b6246f8f2 100644
--- a/ash/touch/touch_hud_debug.cc
+++ b/ash/touch/touch_hud_debug.cc
@@ -371,8 +371,8 @@ TouchHudDebug::~TouchHudDebug() {
 // static
 scoped_ptr<DictionaryValue> TouchHudDebug::GetAllAsDictionary() {
   scoped_ptr<DictionaryValue> value(new DictionaryValue());
-  Shell::RootWindowList roots = Shell::GetInstance()->GetAllRootWindows();
-  for (Shell::RootWindowList::iterator iter = roots.begin();
+  aura::Window::Windows roots = Shell::GetInstance()->GetAllRootWindows();
+  for (aura::Window::Windows::iterator iter = roots.begin();
       iter != roots.end(); ++iter) {
     internal::RootWindowController* controller = GetRootWindowController(*iter);
     internal::TouchHudDebug* hud = controller->touch_hud_debug();