Rename StackingClient -> WindowTreeClient

ui/aura/window.cc

Index: ui/aura/window.cc
diff --git a/ui/aura/window.cc b/ui/aura/window.cc
index e7f0c2a615963d8a4014d72d994da63b493bb8be..2c596be4a23511c4d3a3bb43b8609a193ce20ea7 100644
--- a/ui/aura/window.cc
+++ b/ui/aura/window.cc
@@ -17,7 +17,6 @@
 #include "ui/aura/client/event_client.h"
 #include "ui/aura/client/focus_client.h"
 #include "ui/aura/client/screen_position_client.h"
-#include "ui/aura/client/stacking_client.h"
 #include "ui/aura/client/visibility_client.h"
 #include "ui/aura/env.h"
 #include "ui/aura/layout_manager.h"
@@ -304,19 +303,6 @@ void Window::SchedulePaintInRect(const gfx::Rect& rect) {
   }
 }
 
-void Window::SetDefaultParentByRootWindow(RootWindow* root_window,
-                                          const gfx::Rect& bounds_in_screen) {
-  DCHECK(root_window);
-
-  // Stacking clients are mandatory on RootWindow objects.
-  client::StackingClient* client = client::GetStackingClient(root_window);
-  DCHECK(client);
-
-  aura::Window* default_parent = client->GetDefaultParent(
-      root_window, this, bounds_in_screen);
-  default_parent->AddChild(this);
-}
-
 void Window::StackChildAtTop(Window* child) {
   if (children_.size() <= 1 || child == children_.back())
     return;  // In the front already.