Revert of Replace ValueSetOutputFormatter with HistogramSetJsonOutputFormatter.

telemetry/telemetry/internal/results/histogram_set_json_output_formatter.py

Index: telemetry/telemetry/internal/results/histogram_set_json_output_formatter.py
diff --git a/telemetry/telemetry/internal/results/histogram_set_json_output_formatter.py b/telemetry/telemetry/internal/results/histogram_set_json_output_formatter.py
deleted file mode 100644
index 6c6f397b498dc71dfcbd674834a94e1aed511b70..0000000000000000000000000000000000000000
--- a/telemetry/telemetry/internal/results/histogram_set_json_output_formatter.py
+++ /dev/null
@@ -1,28 +0,0 @@
-# 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 json
-import logging
-
-from telemetry.internal.results import output_formatter
-
-
-class HistogramSetJsonOutputFormatter(output_formatter.OutputFormatter):
-  def __init__(self, output_stream, metadata, reset_results):
-    super(HistogramSetJsonOutputFormatter, self).__init__(output_stream)
-    self._metadata = metadata
-    self._reset_results = reset_results
-
-  def Format(self, page_test_results):
-    histograms = page_test_results.AsHistogramDicts(self._metadata)
-    self._output_stream.seek(0)
-    if not self._reset_results:
-      existing = self._output_stream.read()
-      self._output_stream.seek(0)
-      if existing:
-        try:
-          histograms += json.loads(existing)
-        except ValueError:
-          logging.warn('Found existing histograms json but failed to parse it.')
-    json.dump(histograms, self._output_stream)