Move shell service to toplevel shell namespace

mash/wm/root_window_controller.h

Index: mash/wm/root_window_controller.h
diff --git a/mash/wm/root_window_controller.h b/mash/wm/root_window_controller.h
index 805ce4c5cf4c5d491c9a9611e859e9e8ec7f2cbc..d3f3142112ef315392d349520ee6e39e6e9ec329 100644
--- a/mash/wm/root_window_controller.h
+++ b/mash/wm/root_window_controller.h
@@ -14,14 +14,14 @@
 #include "mash/wm/public/interfaces/container.mojom.h"
 #include "mojo/public/cpp/bindings/binding.h"
 
-namespace mojo {
-class Connector;
-}
-
 namespace mus {
 class WindowManagerClient;
 }
 
+namespace shell {
+class Connector;
+}
+
 namespace ui {
 class Event;
 }
@@ -49,7 +49,7 @@ class RootWindowController : public mus::WindowObserver,
   // Deletes this.
   void Destroy();
 
-  mojo::Connector* GetConnector();
+  shell::Connector* GetConnector();
 
   mus::Window* root() { return root_; }