Update from https://crrev.com/306655

tools/valgrind/scan-build.py

 #!/usr/bin/env python
 # Copyright (c) 2013 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.
 
 import argparse
 import errno
+import json
 import os
 import re
 import sys
 import urllib
 import urllib2
 
 # Where all the data lives.
 ROOT_URL = "http://build.chromium.org/p/chromium.memory.fyi/builders"
 
 # TODO(groby) - support multi-line search from the command line. Useful when
 # scanning for classes of failures, see below.
 SEARCH_STRING = """<p class=\"failure result\">
 Failed memory test: content
 </p>"""
 
 # Location of the log cache.
 CACHE_DIR = "buildlogs.tmp"
 
 # If we don't find anything after searching |CUTOFF| logs, we're probably done.
-CUTOFF = 100
+CUTOFF = 200
 
 def EnsurePath(path):
   """Makes sure |path| does exist, tries to create it if it doesn't."""
   try:
     os.makedirs(path)
   except OSError as exception:
     if exception.errno != errno.EEXIST:
       raise
 
 
@@ skipping 146 matching lines @@
       self._current = 0
     return False
 
 
 def main(argv):
   # Create argument parser.
   parser = argparse.ArgumentParser()
   commands = parser.add_mutually_exclusive_group(required=True)
   commands.add_argument("--update", action='store_true')
   commands.add_argument("--find", metavar='search term')
+  parser.add_argument("--json", action='store_true',
+                      help="Output in JSON format")
   args = parser.parse_args()
 
   path = os.path.abspath(os.path.dirname(argv[0]))
   cache_path = os.path.join(path, CACHE_DIR)
 
   fyi = Waterfall(ROOT_URL, cache_path)
 
   if args.update:
     fyi.Update()
     for builder in fyi.Builders():
       print "Updating", builder.Name()
       builder.ScanLogs(lambda x:False)
 
   if args.find:
+    result = []
     tester = MultiLineChange(args.find.splitlines())
     fyi.FetchInfo()
 
-    print "SCANNING FOR ", args.find
+    if not args.json:
+      print "SCANNING FOR ", args.find
     for builder in fyi.Builders():
-      print "Scanning", builder.Name()
+      if not args.json:
+        print "Scanning", builder.Name()
       occurrences = builder.ScanLogs(tester)
       if occurrences:
         min_build = min(occurrences)
         path = builder.GetBuildPath(min_build)
-        print "Earliest occurrence in build %d" % min_build
-        print "Latest occurrence in build %d" % max(occurrences)
-        print "Latest build: %d" % builder.LatestBuild()
-        print path
-        print "%d total" % len(occurrences)
-
+        if args.json:
+          data = {}
+          data['builder'] = builder.Name()
+          data['first_affected'] = min_build
+          data['last_affected'] = max(occurrences)
+          data['last_build'] = builder.LatestBuild()
+          data['frequency'] = ((int(builder.LatestBuild()) - int(min_build)) /
+              len(occurrences))
+          data['total'] = len(occurrences)
+          data['first_url'] = path
+          result.append(data)
+        else:
+          print "Earliest occurrence in build %d" % min_build
+          print "Latest occurrence in build %d" % max(occurrences)
+          print "Latest build: %d" % builder.LatestBuild()
+          print path
+          print "%d total" % len(occurrences)
+    if args.json:
+      json.dump(result, sys.stdout, indent=2, sort_keys=True)
 
 if __name__ == "__main__":
   sys.exit(main(sys.argv))