Make GetRootWindow() return a Window instead of a RootWindow.

ui/aura/root_window.cc

Index: ui/aura/root_window.cc
diff --git a/ui/aura/root_window.cc b/ui/aura/root_window.cc
index 8cecf479e11c533bca70c1412e514d4790397deb..3afd448d8ca8d1a98a16b9cb65cc3536ca422abf 100644
--- a/ui/aura/root_window.cc
+++ b/ui/aura/root_window.cc
@@ -149,6 +149,7 @@ RootWindow::RootWindow(const CreateParams& params)
       event_factory_(this),
       held_event_factory_(this),
       repostable_event_factory_(this) {
+  set_dispatcher(this);

[sky, 2013/10/24 20:59:46]

You need to set this to NULL in the destructor, otherwise ~Window is going to
use it.

   SetName("RootWindow");
 
   compositor_.reset(new ui::Compositor(host_->GetAcceleratedWidget()));
@@ -613,7 +614,7 @@ void RootWindow::OnWindowAddedToRootWindow(Window* attached) {
 }
 
 void RootWindow::OnWindowRemovedFromRootWindow(Window* detached,
-                                               RootWindow* new_root) {
+                                               Window* new_root) {
   DCHECK(aura::client::GetCaptureWindow(this) != this);
 
   DispatchMouseExitToHidingWindow(detached);
@@ -932,15 +933,15 @@ void RootWindow::DispatchMouseEventRepost(ui::MouseEvent* event) {
   if (event->type() != ui::ET_MOUSE_PRESSED)
     return;
   Window* target = client::GetCaptureWindow(this);
-  RootWindow* root = this;
+  WindowEventDispatcher* dispatcher = this;
   if (!target) {
     target = GetEventHandlerForPoint(event->location());
   } else {
-    root = target->GetRootWindow();
-    CHECK(root);  // Capture window better be in valid root.
+    dispatcher = target->GetDispatcher();
+    CHECK(dispatcher);  // Capture window better be in valid root.
   }
-  root->mouse_pressed_handler_ = NULL;
-  root->DispatchMouseEventToTarget(event, target);
+  dispatcher->mouse_pressed_handler_ = NULL;
+  dispatcher->DispatchMouseEventToTarget(event, target);
 }
 
 bool RootWindow::DispatchMouseEventToTarget(ui::MouseEvent* event,