* Add tests for onBeforePageDisplay hook. A simple gadget repo
implementation, StaticGadgetRepo, is introduced for this.
* Add integrations tests for various gadget load conditions.
* Add test for onUserGetDefaultOptions hook.
* Add tests for GadgetDefinitionNamespaceRepo.
* Convert ResourceLoaderModuleTest to a unit test.
Change-Id: I275380c2bfcaa44770b3946a0a468eaaabef70c0