[Findit] Factoring the gitiles (etc) stuff out into its own directory

appengine/findit/common/repository.py

-# Copyright 2014 The Chromium Authors. All rights reserved.
-# Use of this source code is governed by a BSD-style license that can be
-# found in the LICENSE file.
-
-
-# pylint: disable=E0711, W0613, R0201
-class Repository(object):  # pragma: no cover
-  """An interface for source code repository."""
-
-  def GetChangeLog(self, revision):
-    """Returns the change log of the given revision."""
-    raise NotImplemented()
-
-  def GetChangeLogs(self, start_revision, end_revision, n=1000):
-    """Returns change log list in (start_revision, end_revision]."""
-    raise NotImplemented()
-
-  def GetChangeDiff(self, revision):
-    """Returns the diff of the given revision."""
-    raise NotImplemented()
-
-  def GetBlame(self, path, revision):
-    """Returns blame of the file at ``path`` of the given revision."""
-    raise NotImplemented()
-
-  def GetSource(self, path, revision):
-    """Returns source code of the file at ``path`` of the given revision."""
-    raise NotImplemented()