Only perform dialog Layout() once during Widget::Init().

ui/views/widget/root_view.cc

Index: ui/views/widget/root_view.cc
diff --git a/ui/views/widget/root_view.cc b/ui/views/widget/root_view.cc
index d2455488a7870c1f7a8cf6b19bb97bc009ccb303..cbb47b88b7ce99d171a7b4cc7a1f5457c01611e8 100644
--- a/ui/views/widget/root_view.cc
+++ b/ui/views/widget/root_view.cc
@@ -193,12 +193,6 @@ void RootView::SetContentsView(View* contents_view) {
   if (has_children())
     RemoveAllChildViews(true);
   AddChildView(contents_view);
-
-  // Force a layout now, since the attached hierarchy won't be ready for the
-  // containing window's bounds. Note that we call Layout directly rather than
-  // calling the widget's size changed handler, since the RootView's bounds may
-  // not have changed, which will cause the Layout not to be done otherwise.
-  Layout();
 }
 
 View* RootView::GetContentsView() {