Remove use of wdiff from layout test runner.

third_party/WebKit/Tools/Scripts/webkitpy/layout_tests/port/mac.py

Index: third_party/WebKit/Tools/Scripts/webkitpy/layout_tests/port/mac.py
diff --git a/third_party/WebKit/Tools/Scripts/webkitpy/layout_tests/port/mac.py b/third_party/WebKit/Tools/Scripts/webkitpy/layout_tests/port/mac.py
index 9082f873e14b6fec01a2d4e91f9102e075a54d1b..8ad8758442274d1b9841ab00adc338db7c30d731 100644
--- a/third_party/WebKit/Tools/Scripts/webkitpy/layout_tests/port/mac.py
+++ b/third_party/WebKit/Tools/Scripts/webkitpy/layout_tests/port/mac.py
@@ -92,9 +92,6 @@ class MacPort(base.Port):
     # PROTECTED METHODS
     #
 
-    def _wdiff_missing_message(self):
-        return 'wdiff is not installed; please install from MacPorts or elsewhere'
-
     def path_to_apache(self):
         return '/usr/sbin/httpd'
 
@@ -104,6 +101,3 @@ class MacPort(base.Port):
 
     def _path_to_driver(self, target=None):
         return self._build_path_with_target(target, self.driver_name() + '.app', 'Contents', 'MacOS', self.driver_name())
-
-    def _path_to_wdiff(self):
-        return 'wdiff'