remove all references to weightedDiffMeasure from cluster_telemetry code

cluster_telemetry/telemetry_slave_scripts/write_json_summary.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.
 
 """Module that outputs an JSON summary containing the comparision of images."""
 
 import json
 import optparse
 import os
@@ skipping 130 matching lines @@
           expected_image_locator=image_locator_nopatch,
           actual_image_locator=image_locator_withpatch)
       file_differences.append({
           json_summary_constants.JSONKEY_FILE_NAME: imagefile_nopatch,
           json_summary_constants.JSONKEY_SKP_LOCATION: posixpath.join(
               gs_skp_dir, skpfile_nopatch),
           json_summary_constants.JSONKEY_NUM_PIXELS_DIFFERING:
               diff_record.get_num_pixels_differing(),
           json_summary_constants.JSONKEY_PERCENT_PIXELS_DIFFERING:
               diff_record.get_percent_pixels_differing(),
-          json_summary_constants.JSONKEY_WEIGHTED_DIFF_MEASURE:
-              diff_record.get_weighted_diff_measure(),
           json_summary_constants.JSONKEY_MAX_DIFF_PER_CHANNEL:
               diff_record.get_max_diff_per_channel(),
           json_summary_constants.JSONKEY_PERCEPTUAL_DIFF:
               diff_record.get_perceptual_difference(),
       })
   if file_differences:
     slave_dict[json_summary_constants.JSONKEY_FAILED_FILES_COUNT] = len(
         file_differences)
     with open(output_file_path, 'w') as f:
       f.write(json.dumps(json_summary, indent=4, sort_keys=True))
@@ skipping 91 matching lines @@
     option_parser.error(
         'Must specify img_root, nopatch_json, nopatch_images_base_url, '
         'withpatch_json, withpatch_images_base_url, output_file_path, '
         'gs_output_dir, gs_skp_dir, and slave_num.')
 
   WriteJsonSummary(options.img_root, options.nopatch_json,
                    options.nopatch_images_base_url, options.withpatch_json,
                    options.withpatch_images_base_url, options.output_file_path,
                    options.gs_output_dir, options.gs_skp_dir, options.slave_num,
                    options.add_to_sys_path)