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

build/android/java_cpp_enum.gypi

+# 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.
+
+# This file is meant to be included into a target to provide an action
+# to generate Java source files from a C++ header file containing annotated
+# enum definitions using a Python script.
+#
+# To use this, create a gyp target with the following form:
+#  {
+#    'target_name': 'bitmap_format_java',
+#    'type': 'none',
+#    'variables': {
+#      'source_file': 'ui/android/bitmap_format.h',
+#    },
+#    'includes': [ '../build/android/java_cpp_enum.gypi' ],
+#  },
+#
+# Then have the gyp target which compiles the java code depend on the newly
+# created target.
+
+{
+  'variables': {
+    # Location where all generated Java sources will be placed.
+    'output_dir': '<(SHARED_INTERMEDIATE_DIR)/enums/<(_target_name)',
+    'generator_path': '<(DEPTH)/build/android/gyp/java_cpp_enum.py',
+    'generator_args': '<(output_dir) <(source_file)',
+  },
+  'direct_dependent_settings': {
+    'variables': {
+      # Ensure that the output directory is used in the class path
+      # when building targets that depend on this one.
+      'generated_src_dirs': [
+        '<(output_dir)/',
+      ],
+      # Ensure that the targets depending on this one are rebuilt if the sources
+      # of this one are modified.
+      'additional_input_paths': [
+        '<(source_file)',
+      ],
+    },
+  },
+  'actions': [
+    {
+      'action_name': 'generate_java_constants',
+      'inputs': [
+        '<(DEPTH)/build/android/gyp/util/build_utils.py',
+        '<(generator_path)',
+        '<(source_file)',
+      ],
+      'outputs': [
+        # This is the main reason this is an action and not a rule. Gyp doesn't
+        # properly expand RULE_INPUT_PATH here and so it's impossible to
+        # calculate the list of outputs.
+        '<!@pymod_do_main(java_cpp_enum --print_output_only '
+            '<@(generator_args))',
+      ],
+      'action': [
+        'python', '<(generator_path)', '<@(generator_args)'
+      ],
+      'message': 'Generating Java from cpp header <(source_file)',
+    },
+  ],
+}