Allow menus to stay open during a child view's drag and drop

ui/views/widget/widget.cc

Index: ui/views/widget/widget.cc
diff --git a/ui/views/widget/widget.cc b/ui/views/widget/widget.cc
index d8b203080719216c6279f60c9e4d4af43f88eefe..abe86f02a83a6bdb5c2be1710c44576789fc72b0 100644
--- a/ui/views/widget/widget.cc
+++ b/ui/views/widget/widget.cc
@@ -787,6 +787,7 @@ void Widget::RunShellDrag(View* view,
                           int operation,
                           ui::DragDropTypes::DragEventSource source) {
   dragged_view_ = view;
+  OnDragWillStart();
   native_widget_->RunShellDrag(view, data, location, operation, source);
   // If the view is removed during the drag operation, dragged_view_ is set to
   // NULL.
@@ -794,6 +795,7 @@ void Widget::RunShellDrag(View* view,
     dragged_view_ = NULL;
     view->OnDragDone();
   }
+  OnDragComplete();
 }
 
 void Widget::SchedulePaintInRect(const gfx::Rect& rect) {
@@ -1382,6 +1384,12 @@ void Widget::DestroyRootView() {
   input_method_.reset();
 }
 
+void Widget::OnDragWillStart() {
+}
+
+void Widget::OnDragComplete() {
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 // Widget, private: