Add LoadComponent API in ImageLoader dbus adapter.

chromeos/dbus/fake_image_loader_client.cc

Index: chromeos/dbus/fake_image_loader_client.cc
diff --git a/chromeos/dbus/fake_image_loader_client.cc b/chromeos/dbus/fake_image_loader_client.cc
index 6f9285760f09852f53fa8c9c6936170d4d612f5c..bba05518274574e8eb375dd7451bf18590095d9d 100644
--- a/chromeos/dbus/fake_image_loader_client.cc
+++ b/chromeos/dbus/fake_image_loader_client.cc
@@ -14,5 +14,10 @@ void FakeImageLoaderClient::RegisterComponent(
     const BoolDBusMethodCallback& callback) {
   callback.Run(DBUS_METHOD_CALL_FAILURE, false);
 }
+void FakeImageLoaderClient::LoadComponent(
+    const std::string& name,
+    const StringDBusMethodCallback& callback) {
+  callback.Run(DBUS_METHOD_CALL_FAILURE, "");
+}
 
 }  // namespace chromeos