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

build/android/java_cpp_template.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 generate Java source files from templates that are processed
+# through the host C pre-processor.
+#
+# NOTE: For generating Java conterparts to enums prefer using the java_cpp_enum
+#       rule instead.
+#
+# To use this, create a gyp target with the following form:
+#  {
+#    'target_name': 'android_net_java_constants',
+#    'type': 'none',
+#    'sources': [
+#      'net/android/NetError.template',
+#    ],
+#    'variables': {
+#      'package_name': 'org/chromium/net',
+#      'template_deps': ['base/net_error_list.h'],
+#    },
+#    'includes': [ '../build/android/java_cpp_template.gypi' ],
+#  },
+#
+# The 'sources' entry should only list template file. The template file
+# itself should use the 'ClassName.template' format, and will generate
+# 'gen/templates/<target-name>/<package-name>/ClassName.java. The files which
+# template dependents on and typically included by the template should be listed
+# in template_deps variables. Any change to them will force a rebuild of
+# the template, and hence of any source that depends on it.
+#
+
+{
+  # Location where all generated Java sources will be placed.
+  'variables': {
+    'include_path%': '<(DEPTH)',
+    'output_dir': '<(SHARED_INTERMEDIATE_DIR)/templates/<(_target_name)/<(package_name)',
+  },
+  '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 dependents are rebuilt when sources for this rule change.
+      'additional_input_paths': [
+        '<@(_sources)',
+        '<@(template_deps)',
+      ],
+    },
+  },
+  # Define a single rule that will be apply to each .template file
+  # listed in 'sources'.
+  'rules': [
+    {
+      'rule_name': 'generate_java_constants',
+      'extension': 'template',
+      # Set template_deps as additional dependencies.
+      'variables': {
+        'output_path': '<(output_dir)/<(RULE_INPUT_ROOT).java',
+      },
+      'inputs': [
+        '<(DEPTH)/build/android/gyp/util/build_utils.py',
+        '<(DEPTH)/build/android/gyp/gcc_preprocess.py',
+        '<@(template_deps)'
+      ],
+      'outputs': [
+        '<(output_path)',
+      ],
+      'action': [
+        'python', '<(DEPTH)/build/android/gyp/gcc_preprocess.py',
+        '--include-path=<(include_path)',
+        '--output=<(output_path)',
+        '--template=<(RULE_INPUT_PATH)',
+      ],
+      'message': 'Generating Java from cpp template <(RULE_INPUT_PATH)',
+    }
+  ],
+}