gn: start of format command

tools/gn/format_test_data/012.golden

Index: tools/gn/format_test_data/012.golden
diff --git a/tools/gn/format_test_data/012.golden b/tools/gn/format_test_data/012.golden
new file mode 100644
index 0000000000000000000000000000000000000000..7e3fc989e0214f906f84b6ac2cd0c67ab1f8b320
--- /dev/null
+++ b/tools/gn/format_test_data/012.golden
@@ -0,0 +1,16 @@
+# (A sample top level block comment)
+# Copyright 2014 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.
+
+if (is_win) {
+  # This is some special stuff for Windows
+  sources = [ "win.cc" ]
+} else if (is_linux) {
+  # This is a block comment inside the linux block, but not attached.
+
+  sources = [ "linux.cc" ]
+} else {
+  # A comment with trailing spaces
+  sources = [ "wha.cc" ]
+}