Adds View::GetNativeTheme() to get the NativeTheme. The interesting

ui/views/widget/desktop_root_window_host.h

Index: ui/views/widget/desktop_root_window_host.h
diff --git a/ui/views/widget/desktop_root_window_host.h b/ui/views/widget/desktop_root_window_host.h
index 0f175d37f981ccb2bc30a00286c986937e2be815..7557413a5bfa3d3cbfdb8b59787842a1e877dc8d 100644
--- a/ui/views/widget/desktop_root_window_host.h
+++ b/ui/views/widget/desktop_root_window_host.h
@@ -19,6 +19,10 @@ class ImageSkia;
 class Rect;
 }
 
+namespace ui {
+class NativeTheme;
+}
+
 namespace views {
 class DesktopNativeWidgetAura;
 namespace internal {
@@ -35,6 +39,9 @@ class VIEWS_EXPORT DesktopRootWindowHost {
       DesktopNativeWidgetAura* desktop_native_widget_aura,
       const gfx::Rect& initial_bounds);
 
+  // Return the NativeTheme to use for |window|.
+  static ui::NativeTheme* GetNativeTheme(aura::Window* window);
+
   // Creates the aura resources associated with the native window we built.
   // Caller takes ownership of returned RootWindow.
   virtual aura::RootWindow* Init(aura::Window* content_window,