[Predator] Add CrashData class to process raw json crash data.

appengine/findit/gae_libs/testcase.py

Index: appengine/findit/gae_libs/testcase.py
diff --git a/appengine/findit/gae_libs/testcase.py b/appengine/findit/gae_libs/testcase.py
index 080b01a901bf39f5dcc43937c393b5c376165246..ecdae81f99ef7ef01fd779d454926341be1de6a0 100644
--- a/appengine/findit/gae_libs/testcase.py
+++ b/appengine/findit/gae_libs/testcase.py
@@ -75,4 +75,9 @@ class TestCase(testing.AppengineTestCase):  # pragma: no cover.
 
   def GetMockHttpClient(self, response_for_url=None):
     """Returns mocked http client class."""
-    return MockHttpClient(response_for_url)
+    return MockHttpClient(response_for_url or {})
+
+  def GetMockRepoFactory(self, response_for_url=None):
+    """Returns mocked repository factory."""
+    return GitilesRepository.Factory(
+        self.GetMockHttpClient(response_for_url or {}))