Remove unused methods in Git and related classes.

third_party/WebKit/Tools/Scripts/webkitpy/common/checkout/git_unittest.py

Index: third_party/WebKit/Tools/Scripts/webkitpy/common/checkout/git_unittest.py
diff --git a/third_party/WebKit/Tools/Scripts/webkitpy/common/checkout/git_unittest.py b/third_party/WebKit/Tools/Scripts/webkitpy/common/checkout/git_unittest.py
index 69eaa40ae9fbabded630097cc7b8fed2a87f484e..07f48959df8842fcade12bba01686c393df6e93c 100644
--- a/third_party/WebKit/Tools/Scripts/webkitpy/common/checkout/git_unittest.py
+++ b/third_party/WebKit/Tools/Scripts/webkitpy/common/checkout/git_unittest.py
@@ -57,23 +57,9 @@ class GitTestWithRealFilesystemAndExecutive(unittest.TestCase):
     def _run(self, *args, **kwargs):
         return self.executive.run_command(*args, **kwargs)
 
-    def _run_silent(self, args, **kwargs):
-        self.executive.run_command(args, **kwargs)
-
     def _write_text_file(self, path, contents):
         self.filesystem.write_text_file(path, contents)
 
-    def _write_binary_file(self, path, contents):
-        self.filesystem.write_binary_file(path, contents)
-
-    def _make_diff(self, command, *args):
-        # We use this wrapper to disable output decoding. diffs should be treated as
-        # binary files since they may include text files of multiple different encodings.
-        return self._run([command, 'diff'] + list(args), decode_output=False)
-
-    def _git_diff(self, *args):
-        return self._make_diff('git', *args)
-
     def test_add_list(self):
         self._chdir(self.untracking_checkout_path)
         git = self.untracking_git