Convert chart-json to Histograms.

tracing/bin/valueset2html

 #!/usr/bin/env python
 # 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.
 
 import argparse
 import codecs
 import json
 import sys
 import os
@@ skipping 17 matching lines @@
   parser.add_argument('--json', nargs='+', default=[],
                       help='Zero or more HistogramSet JSON file paths (input).')
   parser.add_argument('--mapresults', nargs='+', default=[],
                       help='Zero or more map results JSON file paths (input).')
   args = parser.parse_args()
 
   histograms = []
 
   for html_path in args.html:
     histograms.extend(results_renderer.ReadExistingResults(
-        open(html_path, 'r')))
+        open(html_path, 'r').read()))
 
   for json_path in args.json:
     histograms.extend(json.load(open(json_path, 'r')))
 
   for json_path in args.mapresults:
     for filename, results in json.load(open(json_path, 'r')).iteritems():
       for histogram in results['pairs']['histograms']:
         histogram['diagnostics']['iteration']['storyUrl'] = filename
         histograms.append(histogram)
 
   open(args.html_path, 'a').close() # Create file if it doesn't exist.
   with codecs.open(args.html_path,
                    mode='r+', encoding='utf-8') as output_stream:
     results_renderer.RenderHTMLView(histograms, output_stream)
 
 if __name__ == '__main__':
   sys.exit(main())