Fix malformed sizes data

Fixes the sizes.py script producing malformed data that couldn't be
converted to histograms. The conversion script expects metric dicts
that contain story dicts, but sizes was essentially only producing
metric dicts.

This pulls out the "identifier" value to be the story name since that
seems to be what the perf dashboard is doing automatically when
uploading in the old format.

Bug: 906685
Change-Id: Ie06f2ff477e3346059473863138478c261712772
Reviewed-on: https://chromium-review.googlesource.com/c/1377195
Reviewed-by: Thomas Anderson <thomasanderson@chromium.org>
Commit-Queue: Brian Sheedy <bsheedy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#616807}

infra/scripts/legacy/scripts/slave/chromium/sizes.py

@@ -407,6 +407,24 @@ def main_win(options, args, results_collector):
   return 0
 
 
+def format_for_histograms_conversion(data):
+  # We need to do two things to the provided data to make it compatible with the
+  # conversion script:
+  # 1. Add a top-level "benchmark_name" key.
+  # 2. Pull out the "identifier" value to be the story name.
+  formatted_data = {}
+  for metric, metric_data in data.iteritems():
+    story = metric_data['identifier']
+    formatted_data[metric] = {
+      story: metric_data.copy()
+    }
+    del formatted_data[metric][story]['identifier']
+  return {
+    'benchmark_name': 'sizes',
+    'charts': formatted_data
+  }
+
+
 def main():
   if sys.platform in ('win32', 'cygwin'):
     default_platform = 'win'
@@ -467,13 +485,10 @@ def main():
 
   if options.output_dir:
     histogram_path = os.path.join(options.output_dir, 'perf_results.json')
-    # We need to add a bit more data to the results, otherwise the conversion
-    # fails due to the provided data being malformed.
-    updated_results = {
-      'format_version': '1.0',
-      'benchmark_name': 'sizes',
-      'charts': results_collector.results,
-    }
+    # We need to add a bit more data to the results and rearrange some things,
+    # otherwise the conversion fails due to the provided data being malformed.
+    updated_results = format_for_histograms_conversion(
+        results_collector.results)
     with open(histogram_path, 'w') as f:
       json.dump(updated_results, f)
     histogram_result = convert_chart_json.ConvertChartJson(histogram_path)