[Culprit-Finder] Seperate gae related part in cache_decorator and gitile repository to gae_libs/

appengine/findit/waterfall/send_notification_for_culprit_pipeline.py

Index: appengine/findit/waterfall/send_notification_for_culprit_pipeline.py
diff --git a/appengine/findit/waterfall/send_notification_for_culprit_pipeline.py b/appengine/findit/waterfall/send_notification_for_culprit_pipeline.py
index b81365c260b3462329efb369ff162e8117176c14..ded03cf38083fcd60dc62ad0dfc44b6d33b11738 100644
--- a/appengine/findit/waterfall/send_notification_for_culprit_pipeline.py
+++ b/appengine/findit/waterfall/send_notification_for_culprit_pipeline.py
@@ -10,9 +10,9 @@ from google.appengine.ext import ndb
 
 from common.http_client_appengine import HttpClientAppengine as HttpClient
 from common.pipeline_wrapper import BasePipeline
+from gae_libs.gitiles.cached_gitiles_repository import CachedGitilesRepository
 from infra_api_clients.codereview.rietveld import Rietveld
 from lib import time_util
-from lib.gitiles.gitiles_repository import GitilesRepository
 from model import analysis_status as status
 from model.wf_analysis import WfAnalysis
 from model.wf_culprit import WfCulprit
@@ -92,7 +92,7 @@ def _GetCulpritInfo(repo_name, revision):
   """Returns commit position/time and code-review url of the given revision."""
   # TODO(stgao): get repo url at runtime based on the given repo name.
   # unused arg - pylint: disable=W0612,W0613
-  repo = GitilesRepository(
+  repo = CachedGitilesRepository(
       HttpClient(), 'https://chromium.googlesource.com/chromium/src.git')
   change_log = repo.GetChangeLog(revision)
   return change_log.commit_position, change_log.code_review_url