Fixes two bugs related to constrained windows:

ui/views/window/client_view.cc

Index: ui/views/window/client_view.cc
diff --git a/ui/views/window/client_view.cc b/ui/views/window/client_view.cc
index 7051d2d222dfc8ebf11830951ad74d61a81c53ea..2d2f26a02d7bd41465628cb91d80a9576942a5d2 100644
--- a/ui/views/window/client_view.cc
+++ b/ui/views/window/client_view.cc
@@ -48,9 +48,13 @@ void ClientView::WidgetClosing() {
 gfx::Size ClientView::GetPreferredSize() {
   // |contents_view_| is allowed to be NULL up until the point where this view
   // is attached to a Container.
-  if (contents_view_)
-    return contents_view_->GetPreferredSize();
-  return gfx::Size();
+  return contents_view_ ? contents_view_->GetPreferredSize() : gfx::Size();
+}
+
+gfx::Size ClientView::GetMinimumSize() {
+  // |contents_view_| is allowed to be NULL up until the point where this view
+  // is attached to a Container.
+  return contents_view_ ? contents_view_->GetMinimumSize() : gfx::Size();
 }
 
 void ClientView::Layout() {