Fix webkit-patch --help.

third_party/WebKit/Tools/Scripts/webkitpy/tool/webkit_patch_unittest.py

Index: third_party/WebKit/Tools/Scripts/webkitpy/tool/webkit_patch_unittest.py
diff --git a/third_party/WebKit/Tools/Scripts/webkitpy/tool/webkit_patch_unittest.py b/third_party/WebKit/Tools/Scripts/webkitpy/tool/webkit_patch_unittest.py
index 67025774f596d85d0fcf8ff2f0cc35b45e950cc8..b6c8db9efee4fb80a54eed7ac2348a95f784cc1a 100644
--- a/third_party/WebKit/Tools/Scripts/webkitpy/tool/webkit_patch_unittest.py
+++ b/third_party/WebKit/Tools/Scripts/webkitpy/tool/webkit_patch_unittest.py
@@ -30,7 +30,7 @@ class WebKitPatchTest(unittest.TestCase):
         self.assertEqual(tool.command_by_name('help').name, 'help')
         self.assertIsNone(tool.command_by_name('non-existent'))
 
-    def test_help(self):
+    def test_help_command(self):
         oc = OutputCapture()
         oc.capture_output()
         tool = WebKitPatch('path')
@@ -39,3 +39,17 @@ class WebKitPatchTest(unittest.TestCase):
         self.assertTrue(out.startswith('Usage: '))
         self.assertEqual('', err)
         self.assertEqual('', logs)
+
+    def test_help_argument(self):
+        oc = OutputCapture()
+        oc.capture_output()
+        tool = WebKitPatch('path')
+        try:
+            tool.main(['tool', '--help'])
+        except SystemExit:
+            pass  # optparse calls sys.exit after showing help.
+        finally:
+            out, err, logs = oc.restore_output()
+        self.assertTrue(out.startswith('Usage: '))
+        self.assertEqual('', err)
+        self.assertEqual('', logs)