mash: remove more shell/shelf WmWindow usage.

ash/test/ash_test_base.cc

Index: ash/test/ash_test_base.cc
diff --git a/ash/test/ash_test_base.cc b/ash/test/ash_test_base.cc
index 2c22ca48476a739fcd36ce4335b4e56900e445e8..d80aa143ffc20200b871578a7817bea2a95bb774 100644
--- a/ash/test/ash_test_base.cc
+++ b/ash/test/ash_test_base.cc
@@ -191,10 +191,7 @@ void AshTestBase::TearDown() {
 
 // static
 WmShelf* AshTestBase::GetPrimaryShelf() {
-  return ShellPort::Get()
-      ->GetPrimaryRootWindow()
-      ->GetRootWindowController()
-      ->GetShelf();
+  return Shell::GetPrimaryRootWindowController()->GetShelf();
 }
 
 // static
@@ -247,9 +244,7 @@ std::unique_ptr<views::Widget> AshTestBase::CreateTestWidget(
   params.delegate = delegate;
   params.ownership = views::Widget::InitParams::WIDGET_OWNS_NATIVE_WIDGET;
   params.bounds = bounds;
-  ShellPort::Get()
-      ->GetPrimaryRootWindow()
-      ->GetRootWindowController()
+  Shell::GetPrimaryRootWindowController()
       ->ConfigureWidgetInitParamsForContainer(widget.get(), container_id,
                                               &params);
   widget->Init(params);