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

build/android/gyp/create_flutter_jar.py

Index: build/android/gyp/create_flutter_jar.py
diff --git a/build/android/gyp/create_flutter_jar.py b/build/android/gyp/create_flutter_jar.py
new file mode 100644
index 0000000000000000000000000000000000000000..c30bae2bd9fecf0aaa748d48372b41e3b3762a81
--- /dev/null
+++ b/build/android/gyp/create_flutter_jar.py
@@ -0,0 +1,56 @@
+#!/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.
+
+"""Create a JAR incorporating all the components required to build a Flutter application"""
+
+import optparse
+import os
+import sys
+import zipfile
+
+from util import build_utils
+
+def main(args):
+  args = build_utils.ExpandFileArgs(args)
+  parser = optparse.OptionParser()
+  build_utils.AddDepfileOption(parser)
+  parser.add_option('--output', help='Path to output jar.')
+  parser.add_option('--dist_jar', help='Flutter shell Java code jar.')
+  parser.add_option('--native_lib', action='append', help='Native code library.')
+  parser.add_option('--android_abi', help='Native code ABI.')
+  parser.add_option('--asset_dir', help='Path to assets.')
+  options, _ = parser.parse_args(args)
+  build_utils.CheckOptions(options, parser, [
+    'output', 'dist_jar', 'native_lib', 'android_abi', 'asset_dir'
+  ])
+
+  input_deps = []
+
+  with zipfile.ZipFile(options.output, 'w', zipfile.ZIP_DEFLATED) as out_zip:
+    input_deps.append(options.dist_jar)
+    with zipfile.ZipFile(options.dist_jar, 'r') as dist_zip:
+      for dist_file in dist_zip.infolist():
+        if dist_file.filename.endswith('.class'):
+          out_zip.writestr(dist_file.filename, dist_zip.read(dist_file.filename))
+
+    for native_lib in options.native_lib:
+      input_deps.append(native_lib)
+      out_zip.write(native_lib,
+                    'lib/%s/%s' % (options.android_abi, os.path.basename(native_lib)))
+
+    for asset_file in os.listdir(options.asset_dir):
+      input_deps.append(asset_file)
+      out_zip.write(os.path.join(options.asset_dir, asset_file),
+                    'assets/%s' % asset_file)
+
+  if options.depfile:
+    build_utils.WriteDepfile(
+        options.depfile,
+        input_deps + build_utils.GetPythonDependencies())
+
+
+if __name__ == '__main__':
+  sys.exit(main(sys.argv[1:]))