Remove pretty_print step from histograms presubmit, git cl format handles this.

tools/metrics/histograms/PRESUBMIT.py

-# Copyright 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.
-
-"""
-See http://dev.chromium.org/developers/how-tos/depottools/presubmit-scripts
-for more details on the presubmit API built into depot_tools.
-"""
-
-
-def CheckChange(input_api, output_api):
-  """Checks that histograms.xml is pretty-printed and well-formatted."""
-  for f in input_api.AffectedTextFiles():
-    p = f.AbsoluteLocalPath()
-    if (input_api.basename(p) == 'histograms.xml'
-        and input_api.os_path.dirname(p) == input_api.PresubmitLocalPath()):
-      cwd = input_api.os_path.dirname(p)
-      exit_code = input_api.subprocess.call(
-          ['python', 'pretty_print.py', '--presubmit'], cwd=cwd)
-      if exit_code != 0:
-        return [output_api.PresubmitError(
-            'histograms.xml is not formatted correctly; run %s/pretty_print.py '
-            'to fix' % input_api.PresubmitLocalPath())]
-
-      exit_code = input_api.subprocess.call(
-          ['python', 'validate_format.py'], cwd=cwd)
-      if exit_code != 0:
-        return [output_api.PresubmitError(
-            'histograms.xml is not well formatted; run %s/validate_format.py '

[Alexei Svitkine (slow), 2017/04/03 15:49:49]

"git cl format" only does the pretty_print.py part - not validate_format.py
(which checks it for semantics).

So I think this part should still remain.

[DaleCurtis, 2017/04/03 18:22:54]

Ah yeah, git cl format has rudimentary validation, but won't catch some of the
histograms specific stuff around enum duplication, etc. It'd be nice if the
validation step could be run on the parsed tree from the formatter (so parsing
isn't done twice), but currently pretty_print_xml is a generic script instead of
specific to histograms.

-            'and fix the reported errors' % input_api.PresubmitLocalPath())]
-  return []
-
-
-def CheckChangeOnUpload(input_api, output_api):
-  return CheckChange(input_api, output_api)
-
-
-def CheckChangeOnCommit(input_api, output_api):
-  return CheckChange(input_api, output_api)