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

ui/views/win/hwnd_util_aurawin.cc

Index: ui/views/win/hwnd_util_aurawin.cc
diff --git a/ui/views/win/hwnd_util_aurawin.cc b/ui/views/win/hwnd_util_aurawin.cc
index 606247893650f6633d49c723f4b54c56b9bacb00..a927df1ee8e8d14f32ac8e77134382b113fa5566 100644
--- a/ui/views/win/hwnd_util_aurawin.cc
+++ b/ui/views/win/hwnd_util_aurawin.cc
@@ -19,21 +19,21 @@ HWND HWNDForWidget(const Widget* widget) {
 
 HWND HWNDForNativeView(const gfx::NativeView view) {
   return view && view->GetRootWindow() ?
-      view->GetRootWindow()->GetAcceleratedWidget() : NULL;
+      view->GetDispatcher()->GetAcceleratedWidget() : NULL;
 }
 
 HWND HWNDForNativeWindow(const gfx::NativeWindow window) {
   return window && window->GetRootWindow() ?
-      window->GetRootWindow()->GetAcceleratedWidget() : NULL;
+      window->GetDispatcher()->GetAcceleratedWidget() : NULL;
 }
 
 gfx::Rect GetWindowBoundsForClientBounds(View* view,
                                          const gfx::Rect& client_bounds) {
   DCHECK(view);
-  aura::RootWindow* window =
-      view->GetWidget()->GetNativeWindow()->GetRootWindow();
-  if (window) {
-    HWND hwnd = window->GetAcceleratedWidget();
+  aura::WindowEventDispatcher* dispatcher =
+      view->GetWidget()->GetNativeWindow()->GetDispatcher();
+  if (dispatcher) {
+    HWND hwnd = dispatcher->GetAcceleratedWidget();
     RECT rect = client_bounds.ToRECT();
     DWORD style = ::GetWindowLong(hwnd, GWL_STYLE);
     DWORD ex_style = ::GetWindowLong(hwnd, GWL_EXSTYLE);