[Telemetry] Ensure run_benchmark sets the default values from AddCommandLineOptions.

tools/telemetry/telemetry/core/browser_options_unittest.py

Index: tools/telemetry/telemetry/core/browser_options_unittest.py
diff --git a/tools/telemetry/telemetry/core/browser_options_unittest.py b/tools/telemetry/telemetry/core/browser_options_unittest.py
index b456f40f30c1c36606871f3b34bc1084674d2bc6..9f016fab7bf25e1aaf365794b84b697abad0d2f8 100644
--- a/tools/telemetry/telemetry/core/browser_options_unittest.py
+++ b/tools/telemetry/telemetry/core/browser_options_unittest.py
@@ -1,6 +1,7 @@
 # Copyright (c) 2012 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 optparse
 import unittest
 
 from telemetry.core import browser_options
@@ -70,3 +71,29 @@ class BrowserOptionsTest(unittest.TestCase):
     parser = options.CreateParser()
     parser.parse_args(['--browser', 'any', '--profile-dir', 'foo'])
     self.assertEquals(options.profile_dir, 'foo')
+
+  def testMergeDefaultValues(self):
+    options = browser_options.BrowserOptions()
+    options.already_true = True
+    options.already_false = False
+    options.override_to_true = False
+    options.override_to_false = True
+
+    parser = optparse.OptionParser()
+    parser.add_option('--already_true', action='store_true')
+    parser.add_option('--already_false', action='store_true')
+    parser.add_option('--unset', action='store_true')
+    parser.add_option('--default_true', action='store_true', default=True)
+    parser.add_option('--default_false', action='store_true', default=False)
+    parser.add_option('--override_to_true', action='store_true', default=False)
+    parser.add_option('--override_to_false', action='store_true', default=True)
+
+    options.MergeDefaultValues(parser.get_default_values())
+
+    self.assertTrue(options.already_true)
+    self.assertFalse(options.already_false)
+    self.assertTrue(options.unset is None)
+    self.assertTrue(options.default_true)
+    self.assertFalse(options.default_false)
+    self.assertFalse(options.override_to_true)
+    self.assertTrue(options.override_to_false)