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

content/test/gpu/run_unittests

Index: content/test/gpu/run_unittests
diff --git a/content/test/gpu/run_unittests b/content/test/gpu/run_unittests
index 9e3186404913303ee87933f340e9f81d54a6bc57..62d8cfee0ec61d068657f0103e1697e14ba678e4 100755
--- a/content/test/gpu/run_unittests
+++ b/content/test/gpu/run_unittests
@@ -15,13 +15,13 @@ import sys
 sys.path.append(os.path.join(os.path.dirname(__file__),
     os.pardir, os.pardir, os.pardir, 'tools', 'telemetry'))
 
-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())