Move shell service to toplevel shell namespace

components/mus/public/cpp/window_tree_connection.h

Index: components/mus/public/cpp/window_tree_connection.h
diff --git a/components/mus/public/cpp/window_tree_connection.h b/components/mus/public/cpp/window_tree_connection.h
index e7d58cc9e31200365292ea7a2fa491ad8428bc37..daa2f682a8dd683c688fc25033fd7f2ab80e52b9 100644
--- a/components/mus/public/cpp/window_tree_connection.h
+++ b/components/mus/public/cpp/window_tree_connection.h
@@ -15,7 +15,7 @@
 #include "components/mus/public/interfaces/window_tree.mojom.h"
 #include "mojo/public/cpp/bindings/interface_request.h"
 
-namespace mojo {
+namespace shell {
 class Connector;
 }
 
@@ -43,7 +43,7 @@ class WindowTreeConnection {
   // Creates a WindowTreeConnection with no roots. Use this to establish a
   // connection directly to mus and create top level windows.
   static WindowTreeConnection* Create(WindowTreeDelegate* delegate,
-                                      mojo::Connector* connector);
+                                      shell::Connector* connector);
 
   // Creates a WindowTreeConnection to service the specified request for
   // a WindowTreeClient. Use this to be embedded in another app.