Add a instance groups to Connect(), and introduce an Identity struct.

mojo/shell/public/cpp/lib/application_test_base.cc

Index: mojo/shell/public/cpp/lib/application_test_base.cc
diff --git a/mojo/shell/public/cpp/lib/application_test_base.cc b/mojo/shell/public/cpp/lib/application_test_base.cc
index 7f8f684d39f506b71424346a156735b9c38176f9..e2e582648b948358aba104aadb679c9aaf186d46 100644
--- a/mojo/shell/public/cpp/lib/application_test_base.cc
+++ b/mojo/shell/public/cpp/lib/application_test_base.cc
@@ -19,9 +19,8 @@ namespace test {
 
 namespace {
 // Share the application name with multiple application tests.
-String g_name;
+shell::mojom::IdentityPtr g_identity;
 uint32_t g_id = shell::mojom::kInvalidInstanceID;
-String g_user_id = shell::mojom::kRootUserID;
 
 // ShellClient request handle passed from the shell in MojoMain, stored in
 // between SetUp()/TearDown() so we can (re-)intialize new ShellConnections.
@@ -45,20 +44,17 @@ class ShellGrabber : public shell::mojom::ShellClient {
  private:
   // shell::mojom::ShellClient implementation.
   void Initialize(shell::mojom::ConnectorPtr connector,
-                  const String& name,
-                  const String& user_id,
+                  shell::mojom::IdentityPtr identity,
                   uint32_t id) override {
-    g_name = name;
+    g_identity = std::move(identity);
     g_id = id;
-    g_user_id = user_id;
     g_shell_client_request = binding_.Unbind();
     g_connector = std::move(connector);
   }
 
   void AcceptConnection(
-      const String& requestor_name,
-      const String& requestor_user_id,
-      uint32_t requestor_id,
+      shell::mojom::IdentityPtr source,
+      uint32_t source_id,
       shell::mojom::InterfaceProviderRequest local_interfaces,
       shell::mojom::InterfaceProviderPtr remote_interfaces,
       Array<String> allowed_interfaces,
@@ -118,12 +114,12 @@ TestHelper::TestHelper(ShellClient* client)
     : shell_connection_(new ShellConnection(
           client == nullptr ? &default_shell_client_ : client,
           std::move(g_shell_client_request))),
-      name_(g_name),
-      userid_(g_user_id),
+      name_(g_identity->name),
+      userid_(g_identity->user_id),
       instance_id_(g_id) {
   // Fake ShellClient initialization.
   shell::mojom::ShellClient* shell_client = shell_connection_.get();
-  shell_client->Initialize(std::move(g_connector), g_name, g_user_id, g_id);
+  shell_client->Initialize(std::move(g_connector), std::move(g_identity), g_id);
 }
 
 TestHelper::~TestHelper() {