Extract diff_text function out of the Port class.

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

Index: third_party/WebKit/Tools/Scripts/webkitpy/layout_tests/port/base.py
diff --git a/third_party/WebKit/Tools/Scripts/webkitpy/layout_tests/port/base.py b/third_party/WebKit/Tools/Scripts/webkitpy/layout_tests/port/base.py
index 8a211699dcb9fff6fd932666e19fd336a43042c2..8455ba5155cc205801c226f16688fd6865cf21c1 100644
--- a/third_party/WebKit/Tools/Scripts/webkitpy/layout_tests/port/base.py
+++ b/third_party/WebKit/Tools/Scripts/webkitpy/layout_tests/port/base.py
@@ -517,36 +517,6 @@ class Port(object):
 
         return (result, err_str or None)
 
-    def diff_text(self, expected_text, actual_text, expected_filename, actual_filename):
-        """Returns a string containing the diff of the two text strings
-        in 'unified diff' format.
-        """
-
-        # The filenames show up in the diff output, make sure they're
-        # raw bytes and not unicode, so that they don't trigger join()
-        # trying to decode the input.
-        def to_raw_bytes(string_value):
-            if isinstance(string_value, unicode):
-                return string_value.encode('utf-8')
-            return string_value
-        expected_filename = to_raw_bytes(expected_filename)
-        actual_filename = to_raw_bytes(actual_filename)
-        diff = difflib.unified_diff(expected_text.splitlines(True),
-                                    actual_text.splitlines(True),
-                                    expected_filename,
-                                    actual_filename)
-
-        # The diff generated by the difflib is incorrect if one of the files
-        # does not have a newline at the end of the file and it is present in
-        # the diff. Relevant Python issue: http://bugs.python.org/issue2142
-        def diff_fixup(diff):
-            for line in diff:
-                yield line
-                if not line.endswith('\n'):
-                    yield '\n\\ No newline at end of file\n'
-
-        return ''.join(diff_fixup(diff))
-
     def driver_name(self):
         if self.get_option('driver_name'):
             return self.get_option('driver_name')