Refactor DirectoryFragment.Model to be a static class. Introduce some unit tests. BUG=23754695 Change-Id: Iaa064292ab26b23ac7247e49c05ba91033d84a18
Refactor DirectoryFragment.Model to be a static class. Introduce some unit tests. BUG=23754695 Change-Id: Iaa064292ab26b23ac7247e49c05ba91033d84a18