Move shell service to toplevel shell namespace

mojo/public/cpp/bindings/tests/versioning_test_service.cc

Index: mojo/public/cpp/bindings/tests/versioning_test_service.cc
diff --git a/mojo/public/cpp/bindings/tests/versioning_test_service.cc b/mojo/public/cpp/bindings/tests/versioning_test_service.cc
index 082178eb981eac673a05324c4865932fc52771ca..43020f49d524320b1c900366c6e1a04df8937c40 100644
--- a/mojo/public/cpp/bindings/tests/versioning_test_service.cc
+++ b/mojo/public/cpp/bindings/tests/versioning_test_service.cc
@@ -95,12 +95,12 @@ class HumanResourceDatabaseImpl : public HumanResourceDatabase {
 };
 
 class HumanResourceSystemServer
-    : public ShellClient,
+    : public shell::ShellClient,
       public InterfaceFactory<HumanResourceDatabase> {
  public:
   HumanResourceSystemServer() {}
 
-  // mojo::ShellClient implementation.
+  // shell::ShellClient implementation.
   bool AcceptConnection(Connection* connection) override {
     connection->AddInterface<HumanResourceDatabase>(this);
     return true;