[tools/perf] Don't output in the same format twice

This CL restores the accidentally deleted fix for repeated --output-format
arguments.

Bug: 1023796
Change-Id: I247332772af7feb308d00564766b0ca898904cc1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1911790
Commit-Queue: Mikhail Khokhlov <khokhlov@google.com>
Reviewed-by: Juan Antonio Navarro Pérez <perezju@chromium.org>
Cr-Commit-Position: refs/heads/master@{#714589}

tools/perf/core/results_processor/command_line.py

@@ -139,7 +139,9 @@ def ProcessOptions(options):
 
   if not options.output_formats:
     options.output_formats = ['html']
-  elif 'none' in options.output_formats:
+  else:
+    options.output_formats = sorted(set(options.output_formats))
+  if 'none' in options.output_formats:
     options.output_formats.remove('none')
 
 

tools/perf/core/results_processor/command_line_unittest.py

@@ -129,6 +129,12 @@ class TestProcessOptions(ProcessOptionsTestCase):
     with self.assertRaises(SystemExit):
       self.ParseArgs(['--output-format', 'unknown'])
 
+  def testNoDuplicateOutputFormats(self):
+    options = self.ParseArgs(
+        ['--output-format', 'html', '--output-format', 'csv',
+         '--output-format', 'html', '--output-format', 'csv'])
+    self.assertEqual(options.output_formats, ['csv', 'html'])
+
 
 class StandaloneTestProcessOptions(ProcessOptionsTestCase):
   def setUp(self):