Add a snapshot of flutter/engine/src/build to our sdk

build/gyp_chromium.py

Index: build/gyp_chromium.py
diff --git a/build/gyp_chromium.py b/build/gyp_chromium.py
new file mode 100644
index 0000000000000000000000000000000000000000..f9e8ac8ed83f922bbf9385ccbe1b05bbc88d6171
--- /dev/null
+++ b/build/gyp_chromium.py
@@ -0,0 +1,18 @@
+# Copyright 2012 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.
+
+# This file is (possibly, depending on python version) imported by
+# gyp_chromium when GYP_PARALLEL=1 and it creates sub-processes
+# through the multiprocessing library.
+
+# Importing in Python 2.6 (fixed in 2.7) on Windows doesn't search for
+# imports that don't end in .py (and aren't directories with an
+# __init__.py). This wrapper makes "import gyp_chromium" work with
+# those old versions and makes it possible to execute gyp_chromium.py
+# directly on Windows where the extension is useful.
+
+import os
+
+path = os.path.abspath(os.path.split(__file__)[0])
+execfile(os.path.join(path, 'gyp_chromium'))