diff --git a/clang_format_merge_driver b/clang_format_merge_driver
new file mode 100755
index 000000000..8b7904946
--- /dev/null
+++ b/clang_format_merge_driver
@@ -0,0 +1,8 @@
+#!/usr/bin/env bash
+# Copyright 2016 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.
+
+base_dir=$(dirname "$0")
+
+PYTHONDONTWRITEBYTECODE=1 exec python "$base_dir/clang_format_merge_driver.py" "$@"
diff --git a/clang_format_merge_driver.bat b/clang_format_merge_driver.bat
new file mode 100755
index 000000000..848724959
--- /dev/null
+++ b/clang_format_merge_driver.bat
@@ -0,0 +1,11 @@
+@echo off
+:: Copyright 2016 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.
+setlocal
+
+:: This is required with cygwin only.
+PATH=%~dp0;%PATH%
+
+:: Defer control.
+%~dp0python "%~dp0\clang_format_merge_driver.py" %*
diff --git a/clang_format_merge_driver.py b/clang_format_merge_driver.py
new file mode 100755
index 000000000..5f0449a28
--- /dev/null
+++ b/clang_format_merge_driver.py
@@ -0,0 +1,58 @@
+#!/usr/bin/env python
+# Copyright 2016 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.
+"""clang-format 3-way merge driver.
+
+This is a custom merge driver for git that helps automatically resolves
+conflicts caused by clang-format changes. The conflict resolution
+strategy is extremely simple: it simply clang-formats the current,
+ancestor branch's, and other branch's version of the file and delegates
+the remaining work to git merge-file.
+
+See https://git-scm.com/docs/gitattributes ("Defining a custom merge
+driver") for more details.
+"""
+
+import subprocess
+import sys
+
+import clang_format
+
+
+def main():
+ if len(sys.argv) < 5:
+ print('usage: %s ' %
+ sys.argv[0])
+ sys.exit(1)
+
+ base, current, others, file_name_in_tree = sys.argv[1:5]
+ print 'Running clang-format 3-way merge driver on ' + file_name_in_tree
+
+ try:
+ tool = clang_format.FindClangFormatToolInChromiumTree()
+ for fpath in base, current, others:
+ # Typically, clang-format is used with the -i option to rewrite files
+ # in-place. However, merge files live in the repo root, so --style=file
+ # will always pick up the root .clang-format.
+ #
+ # Instead, this tool uses --assume-filename so clang-format will pick up
+ # the appropriate .clang-format. Unfortunately, --assume-filename only
+ # works when the input is from stdin, so the file I/O portions are lifted
+ # up into the script as well.
+ with open(fpath, 'rb') as input_file:
+ output = subprocess.check_output(
+ [tool, '--assume-filename=%s' % file_name_in_tree, '--style=file'],
+ stdin=input_file)
+ with open(fpath, 'wb') as output_file:
+ output_file.write(output)
+ except clang_format.NotFoundError, e:
+ print e
+ print 'Failed to find clang-format. Falling-back on standard 3-way merge'
+
+ return subprocess.call(['git', 'merge-file', '-Lcurrent', '-Lbase', '-Lother',
+ current, base, others])
+
+
+if __name__ == '__main__':
+ sys.exit(main())