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

build/apk_browsertest.gypi

+# Copyright 2015 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 build APK-based browser test suites.
+#
+# To use this, create a gyp target with the following form:
+# {
+#   'target_name': 'test_suite_name_apk',
+#   'type': 'none',
+#   'variables': {
+#     'test_suite_name': 'test_suite_name',  # string
+#     'java_in_dir': 'path/to/java/dir',
+#   },
+#   'includes': ['path/to/this/gypi/file'],
+# }
+#
+
+{
+  'dependencies': [
+    '<(DEPTH)/base/base.gyp:base_java',
+    '<(DEPTH)/build/android/pylib/device/commands/commands.gyp:chromium_commands',
+    '<(DEPTH)/build/android/pylib/remote/device/dummy/dummy.gyp:remote_device_dummy_apk',
+    '<(DEPTH)/testing/android/appurify_support.gyp:appurify_support_java',
+    '<(DEPTH)/testing/android/native_test.gyp:native_test_java',
+    '<(DEPTH)/tools/android/android_tools.gyp:android_tools',
+  ],
+  'conditions': [
+     ['OS == "android"', {
+       'variables': {
+         # These are used to configure java_apk.gypi included below.
+         'apk_name': '<(test_suite_name)',
+         'intermediate_dir': '<(PRODUCT_DIR)/<(test_suite_name)_apk',
+         'final_apk_path': '<(intermediate_dir)/<(test_suite_name)-debug.apk',
+         'native_lib_target': 'lib<(test_suite_name)',
+         # TODO(yfriedman, cjhopman): Support managed installs for gtests.
+         'gyp_managed_install': 0,
+       },
+       'includes': [ 'java_apk.gypi' ],
+     }],  # 'OS == "android"
+  ],  # conditions
+}