[Findit] Pass changed files info to Fracas, 2 face design.

appengine/findit/crash/scorers/top_frame_index.py

 # Copyright 2016 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.
 
 """TopFrameIndex scorer applies to all Result objects.
 
 It represents a heuristic rule:
   The less the top frame index (this result changed) is, the higher score.
 """
 
@@ skipping 22 matching lines @@
 
   def Score(self, top_frame_index):
     # TODO(katesonia): experiment the model and parameters later.
     if top_frame_index < self.max_top_n:
       return 1 - top_frame_index / float(self.max_top_n)
 
     return 0
 
   def Reason(self, top_frame_index, score):
     if score == 0:
-      return ''
+      return None
 
-    return 'Modified top crashing frame is #%d' % top_frame_index
+    return self.name, score, 'Top frame is #%d' % top_frame_index
+
+  def ChangedFiles(self, result):
+    # There is no changed file infos that top frame scorer can provide.
+    return None