Add ability to output ImageBaseGSUrl to render_picture and use in rebaseline server

gm/rebaseline_server/compare_to_expectations.py

 #!/usr/bin/python
 
 """
 Copyright 2013 Google Inc.
 
 Use of this source code is governed by a BSD-style license that can be
 found in the LICENSE file.
 
 Repackage expected/actual GM results as needed by our HTML rebaseline viewer.
 """
@@ skipping 329 matching lines @@
             updated_result_type = result_type
           extra_columns_dict = {
               results.KEY__EXTRACOLUMNS__RESULT_TYPE: updated_result_type,
               results.KEY__EXTRACOLUMNS__BUILDER: builder,
               results.KEY__EXTRACOLUMNS__TEST: test,
               results.KEY__EXTRACOLUMNS__CONFIG: config,
           }
           try:
             image_pair = imagepair.ImagePair(
                 image_diff_db=self._image_diff_db,
-                base_url=gm_json.GM_ACTUALS_ROOT_HTTP_URL,
+                imageA_base_url=gm_json.GM_ACTUALS_ROOT_HTTP_URL,
+                imageB_base_url=gm_json.GM_ACTUALS_ROOT_HTTP_URL,
                 imageA_relative_url=expected_image_relative_url,
                 imageB_relative_url=actual_image_relative_url,
                 expectations=expectations_dict,
                 extra_columns=extra_columns_dict)
             all_image_pairs.add_image_pair(image_pair)
             if updated_result_type != results.KEY__RESULT_TYPE__SUCCEEDED:
               failing_image_pairs.add_image_pair(image_pair)
           except Exception:
             logging.exception('got exception while creating new ImagePair')
 
@@ skipping 44 matching lines @@
       actuals_root=args.actuals,
       expected_root=args.expectations,
       ignore_failures_file=args.ignore_failures_file)
   gm_json.WriteToFile(
       results_obj.get_packaged_results_of_type(results_type=args.results),
       args.outfile)
 
 
 if __name__ == '__main__':
   main()