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

build/java_prebuilt.gypi

+# Copyright (c) 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 meant to be included into a target to provide a rule
+# to package prebuilt Java JARs in a consistent manner.
+#
+# To use this, create a gyp target with the following form:
+# {
+#   'target_name': 'my-package_java',
+#   'type': 'none',
+#   'variables': {
+#     'jar_path': 'path/to/your.jar',
+#   },
+#   'includes': ['path/to/this/gypi/file'],
+# }
+#
+# Required variables:
+#  jar_path - The path to the prebuilt Java JAR file.
+
+{
+  'dependencies': [
+    '<(DEPTH)/build/android/setup.gyp:build_output_dirs'
+  ],
+  'variables': {
+    'dex_path': '<(PRODUCT_DIR)/lib.java/<(_target_name).dex.jar',
+    'intermediate_dir': '<(SHARED_INTERMEDIATE_DIR)/<(_target_name)',
+    'android_jar': '<(android_sdk)/android.jar',
+    'input_jars_paths': [ '<(android_jar)' ],
+    'neverlink%': 0,
+    'proguard_config%': '',
+    'proguard_preprocess%': '0',
+    'variables': {
+      'variables': {
+        'proguard_preprocess%': 0,
+      },
+      'conditions': [
+        ['proguard_preprocess == 1', {
+          'dex_input_jar_path': '<(intermediate_dir)/<(_target_name).pre.jar'
+        }, {
+          'dex_input_jar_path': '<(jar_path)'
+        }],
+      ],
+    },
+    'dex_input_jar_path': '<(dex_input_jar_path)',
+  },
+  'all_dependent_settings': {
+    'variables': {
+      'input_jars_paths': ['<(dex_input_jar_path)'],
+      'conditions': [
+        ['neverlink == 1', {
+          'library_dexed_jars_paths': [],
+        }, {
+          'library_dexed_jars_paths': ['<(dex_path)'],
+        }],
+      ],
+    },
+  },
+  'conditions' : [
+    ['proguard_preprocess == 1', {
+      'actions': [
+        {
+          'action_name': 'proguard_<(_target_name)',
+          'message': 'Proguard preprocessing <(_target_name) jar',
+          'inputs': [
+            '<(android_sdk_root)/tools/proguard/lib/proguard.jar',
+            '<(DEPTH)/build/android/gyp/util/build_utils.py',
+            '<(DEPTH)/build/android/gyp/proguard.py',
+            '<(jar_path)',
+            '<(proguard_config)',
+          ],
+          'outputs': [
+            '<(dex_input_jar_path)',
+          ],
+          'action': [
+            'python', '<(DEPTH)/build/android/gyp/proguard.py',
+            '--proguard-path=<(android_sdk_root)/tools/proguard/lib/proguard.jar',
+            '--input-path=<(jar_path)',
+            '--output-path=<(dex_input_jar_path)',
+            '--proguard-config=<(proguard_config)',
+            '--classpath=>(input_jars_paths)',
+          ]
+        },
+      ],
+    }],
+    ['neverlink == 0', {
+      'actions': [
+        {
+          'action_name': 'dex_<(_target_name)',
+          'message': 'Dexing <(_target_name) jar',
+          'variables': {
+            'dex_input_paths': [
+              '<(dex_input_jar_path)',
+            ],
+            'output_path': '<(dex_path)',
+          },
+          'includes': [ 'android/dex_action.gypi' ],
+        },
+      ],
+    }],
+  ],
+}