Wires up drag/drop for aura-mus

ui/aura/client/drag_drop_delegate.cc

Index: ui/aura/client/drag_drop_delegate.cc
diff --git a/ui/wm/public/drag_drop_delegate.cc b/ui/aura/client/drag_drop_delegate.cc
similarity index 75%
rename from ui/wm/public/drag_drop_delegate.cc
rename to ui/aura/client/drag_drop_delegate.cc
index 6380f963fbfde5e1ed4938f2e935bd195dc5399f..975a671cde311bf1c8c3de6419c2b50b7009fa92 100644
--- a/ui/wm/public/drag_drop_delegate.cc
+++ b/ui/aura/client/drag_drop_delegate.cc
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "ui/wm/public/drag_drop_delegate.h"
+#include "ui/aura/client/drag_drop_delegate.h"
 
 #include "ui/aura/window.h"
 #include "ui/aura/window_property.h"
@@ -12,8 +12,9 @@ DECLARE_WINDOW_PROPERTY_TYPE(aura::client::DragDropDelegate*)
 namespace aura {
 namespace client {
 
-DEFINE_LOCAL_WINDOW_PROPERTY_KEY(
-    DragDropDelegate*, kDragDropDelegateKey, NULL);
+DEFINE_LOCAL_WINDOW_PROPERTY_KEY(DragDropDelegate*,
+                                 kDragDropDelegateKey,
+                                 nullptr);
 
 void SetDragDropDelegate(Window* window, DragDropDelegate* delegate) {
   window->SetProperty(kDragDropDelegateKey, delegate);