Removing the mutation in the factories for getting dep repositories

appengine/findit/gae_libs/gitiles/cached_gitiles_repository.py

Index: appengine/findit/gae_libs/gitiles/cached_gitiles_repository.py
diff --git a/appengine/findit/gae_libs/gitiles/cached_gitiles_repository.py b/appengine/findit/gae_libs/gitiles/cached_gitiles_repository.py
index 1aa50d98e16d5d1eafd756075acabdcd8ef577fc..70f2426dab68fd979a25ccfb5c70a659d7e11f60 100644
--- a/appengine/findit/gae_libs/gitiles/cached_gitiles_repository.py
+++ b/appengine/findit/gae_libs/gitiles/cached_gitiles_repository.py
@@ -23,3 +23,19 @@ class CachedGitilesRepository(GitilesRepository):
           cache=PickledMemCache())
   def _SendRequestForTextResponse(self, url):  # pragma: no cover
     return super(CachedGitilesRepository, self)._SendRequestForTextResponse(url)
+
+  @classmethod
+  def Factory(cls, http_client): # pragma: no cover

[Sharu Jiang, 2016/12/30 00:00:46]

This is general enough that we can move this to ``GitilesRepository``

[wrengr, 2017/01/03 19:01:02]

Done.

+    """Construct a factory for creating ``CachedGitilesRepository`` instances.
+
+    Args:
+      http_client: the http client to be shared among all created repository
+        instances.
+
+    Returns:
+      A function from repo urls to ``CachedGitilesRepository``
+      instances. All instances produced by this function are novel
+      (i.e., newly allocated), but they all share the same underlying
+      ``http_client``.
+    """
+    return lambda repo_url: cls(http_client, repo_url)