For consistency with benchmark, rename unittest.output_formatter -> progress_reporter.

tools/chrome_proxy/run_tests

 #!/usr/bin/env python
 # Copyright 2014 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.
 
 """This script runs unit tests of the code in the perf directory.
 
 This script DOES NOT run benchmarks. run_benchmark does that.
 """
 
 import os
 import sys
 
 sys.path.append(os.path.join(os.path.dirname(__file__), os.pardir, 'telemetry'))
 sys.path.append(os.path.join(os.path.dirname(__file__), os.pardir, 'perf'))
 
-from telemetry.unittest import gtest_output_formatter
+from telemetry.unittest import gtest_progress_reporter
 from telemetry.unittest import run_tests
 
 
 if __name__ == '__main__':
   base_dir = os.path.dirname(os.path.realpath(__file__))
-  output_formatters = [
-      gtest_output_formatter.GTestOutputFormatter(sys.stdout)]
-  run_tests.config = run_tests.Config(base_dir, [base_dir], output_formatters)
+  progress_reporters = [
+      gtest_progress_reporter.GTestProgressReporter(sys.stdout)]
+  run_tests.config = run_tests.Config(base_dir, [base_dir], progress_reporters)
   sys.exit(run_tests.RunTestsCommand.main())