Add check_gn_headers.py to find missing headers in GN

build/check_gn_headers_unittest.py

Index: build/check_gn_headers_unittest.py
diff --git a/build/check_gn_headers_unittest.py b/build/check_gn_headers_unittest.py
new file mode 100755
index 0000000000000000000000000000000000000000..fa1650fafcf6d5ac84e761e4bdf59f853ad3e797
--- /dev/null
+++ b/build/check_gn_headers_unittest.py
@@ -0,0 +1,86 @@
+#!/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.
+
+import logging
+import json
+import os
+import unittest
+import check_gn_headers
+
+
+ninja_input = r'''
+obj/a.o: #deps 1, deps mtime 123 (VALID)
+    ../../a.cc
+    ../../dir/path/b.h
+    ../../c.hh
+
+obj/b.o: #deps 1, deps mtime 123 (STALE)
+    ../../b.cc
+    ../../dir2/path/b.h
+    ../../c2.hh
+
+obj/c.o: #deps 1, deps mtime 123 (VALID)
+    ../../c.cc
+    ../../build/a.h
+    gen/b.h
+    ../../dir3/path/b.h
+    ../../c3.hh
+'''
+ninja_input_win = ninja_input.replace('/', '\\')
+
+
+gn_input = json.loads(r'''
+{
+   "others": [],
+   "targets": {
+      "//:All": {
+      },
+      "//:base": {
+         "sources": [ "//base/a.cc", "//base/a.h", "//base/b.hh" ],
+         "visibility": [ "*" ]
+      }
+    }
+}
+''')
+
+
+class CheckGnHeadersTest(unittest.TestCase):
+  def testNinja(self):
+    headers = check_gn_headers.extract_d_headers(ninja_input)
+    expected = set([
+        'dir/path/b.h',
+        'c.hh',
+        'dir3/path/b.h',
+        'c3.hh',
+    ])
+    self.assertEquals(headers, expected)
+
+  def testNinjaWin(self):
+    old_sep = os.sep
+    os.sep = '\\'
+
+    headers = check_gn_headers.extract_d_headers(ninja_input_win)
+    expected = set([
+        'dir\\path\\b.h',
+        'c.hh',
+        'dir3\\path\\b.h',
+        'c3.hh',
+    ])
+    self.assertEquals(headers, expected)
+
+    os.sep = old_sep
+
+  def testGn(self):
+    headers = check_gn_headers.extract_gn_headers(gn_input)
+    expected = set([
+        'base/a.h',
+        'base/b.hh',
+    ])
+    self.assertEquals(headers, expected)
+
+
+if __name__ == '__main__':
+  logging.getLogger().setLevel(logging.DEBUG)
+  unittest.main(verbosity=2)