Add child for parent_mus when params.parent_mus is not initialized.

ui/views/mus/native_widget_mus.cc

Index: ui/views/mus/native_widget_mus.cc
diff --git a/ui/views/mus/native_widget_mus.cc b/ui/views/mus/native_widget_mus.cc
index bfce92136a3e543ab7ce4bb89e6533b7ddb9f097..3b78af79b5b95ec93a62a891df58431c4e1a328f 100644
--- a/ui/views/mus/native_widget_mus.cc
+++ b/ui/views/mus/native_widget_mus.cc
@@ -775,17 +775,20 @@ void NativeWidgetMus::InitNativeWidget(const Widget::InitParams& params) {
   content_->set_ignore_events(!params.accept_events);
   hosted_window->AddChild(content_);
 
+  if (params.parent_mus)

[mfomitchev, 2016/11/07 18:19:23]

Can we make it so we only do AddChild once? Something like this:

ui::Window* parent_mus = params.parent_mus;

// Set-up transiency if appropriate.
if (params.parent && !params.child) {
  aura::Window* parent_root_aura = params.parent->GetRootWindow();
  ui::Window* parent_root_mus = parent_root_aura->GetProperty(kMusWindow);
  if (parent_root_mus) {
     parent_root_mus->AddTransientWindow(window_);
     if (!parent_mus)
       parent_mus = parent_root_mus;
  }
}

parent_mus->AddChild(window_);

[thanhph, 2016/11/07 19:50:56]

Thanks. I also add the if condition to prevent SEGV error. 

if (parent_mus)
    parent_mus->AddChild(window_);

Manual test work with this refactor.

[mfomitchev, 2016/11/07 20:16:47]

Cool, thanks!

+    params.parent_mus->AddChild(window_);
+
   // Set-up transiency if appropriate.
   if (params.parent && !params.child) {
     aura::Window* parent_root = params.parent->GetRootWindow();
     ui::Window* parent_mus = parent_root->GetProperty(kMusWindow);
-    if (parent_mus)
+    if (parent_mus) {
       parent_mus->AddTransientWindow(window_);
+      if (!params.parent_mus)
+        parent_mus->AddChild(window_);
+    }
   }
 
-  if (params.parent_mus)
-    params.parent_mus->AddChild(window_);
-
   // TODO(sky): deal with show state.
   if (!params.bounds.size().IsEmpty())
     SetBounds(params.bounds);