Converts DockedWindowLayoutManager to common ash/wm types

ash/wm/aura/wm_root_window_controller_aura.cc

Index: ash/wm/aura/wm_root_window_controller_aura.cc
diff --git a/ash/wm/aura/wm_root_window_controller_aura.cc b/ash/wm/aura/wm_root_window_controller_aura.cc
index ad249fe0136a57b92a236b8bc97624ad88d7d278..306827981749375f352404c4ee3b7f255dda2c14 100644
--- a/ash/wm/aura/wm_root_window_controller_aura.cc
+++ b/ash/wm/aura/wm_root_window_controller_aura.cc
@@ -76,5 +76,12 @@ WmWindow* WmRootWindowControllerAura::GetWindow() {
   return WmWindowAura::Get(root_window_controller_->GetRootWindow());
 }
 
+void WmRootWindowControllerAura::ConfigureWidgetInitParamsForContainer(
+    views::Widget* widget,
+    int shell_container_id,
+    views::Widget::InitParams* init_params) {
+  init_params->parent = Shell::GetContainer(
+      root_window_controller_->GetRootWindow(), shell_container_id);
+}
 }  // namespace wm
 }  // namespace ash