[Findit] Initial code of findit for crash. Add scorers to apply heuristic rules.

appengine/findit/crash/scorers/aggregator.py

Index: appengine/findit/crash/scorers/aggregator.py
diff --git a/appengine/findit/crash/scorers/aggregator.py b/appengine/findit/crash/scorers/aggregator.py
new file mode 100644
index 0000000000000000000000000000000000000000..085dc581a2439a11f84894f6b1345fdb878654a7
--- /dev/null
+++ b/appengine/findit/crash/scorers/aggregator.py
@@ -0,0 +1,25 @@
+# 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.
+
+"""Aggregator aggregates all the scorers passed in, multiplies scores
+together and combines reasons and summaries the result."""
+
+
+class Aggregator(object):
+
+  def __init__(self, scorers):
+    self.scorers = scorers
+
+  def ScoreAndReason(self, result):
+    score = 1.0
+    reason = ''
+    for i, scorer in enumerate(self.scorers):
+      curr_score, curr_reason = scorer(result)

[stgao, 2016/04/15 18:35:19]

no abbreviation.

[Sharu, 2016/04/15 22:59:47]

Done.

+      score *= curr_score

[stgao, 2016/04/15 18:35:19]

So we change from a vector of scores to multiplying all scores?
Do you plan to run some experiment to compare both approach?

[Sharu, 2016/04/15 22:59:47]

Add a TODO here to compare these 2 methods later.

+      reason += '%d. %s (score: %d)\n' % (i + 1, curr_reason, curr_score)
+
+    reason += '\n%s' % str(result)
+
+    result.confidence = score
+    result.reason = reason