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

build/android/envsetup.sh

Index: build/android/envsetup.sh
diff --git a/build/android/envsetup.sh b/build/android/envsetup.sh
new file mode 100755
index 0000000000000000000000000000000000000000..0545330bb2b0860441dbb48f48e3d76ed6dafaae
--- /dev/null
+++ b/build/android/envsetup.sh
@@ -0,0 +1,62 @@
+#!/bin/bash
+# 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.
+
+# Sets up environment for building Chromium on Android.
+
+# Make sure we're being sourced (possibly by another script). Check for bash
+# since zsh sets $0 when sourcing.
+if [[ -n "$BASH_VERSION" && "${BASH_SOURCE:-$0}" == "$0" ]]; then
+  echo "ERROR: envsetup must be sourced."
+  exit 1
+fi
+
+# This only exists to set local variables. Don't call this manually.
+android_envsetup_main() {
+  local SCRIPT_PATH="$1"
+  local SCRIPT_DIR="$(dirname "$SCRIPT_PATH")"
+
+  local CURRENT_DIR="$(readlink -f "${SCRIPT_DIR}/../../")"
+  if [[ -z "${CHROME_SRC}" ]]; then
+    # If $CHROME_SRC was not set, assume current directory is CHROME_SRC.
+    local CHROME_SRC="${CURRENT_DIR}"
+  fi
+
+  if [[ "${CURRENT_DIR/"${CHROME_SRC}"/}" == "${CURRENT_DIR}" ]]; then
+    # If current directory is not in $CHROME_SRC, it might be set for other
+    # source tree. If $CHROME_SRC was set correctly and we are in the correct
+    # directory, "${CURRENT_DIR/"${CHROME_SRC}"/}" will be "".
+    # Otherwise, it will equal to "${CURRENT_DIR}"
+    echo "Warning: Current directory is out of CHROME_SRC, it may not be \
+  the one you want."
+    echo "${CHROME_SRC}"
+  fi
+
+  # Allow the caller to override a few environment variables. If any of them is
+  # unset, we default to a sane value that's known to work. This allows for
+  # experimentation with a custom SDK.
+  if [[ -z "${ANDROID_SDK_ROOT}" || ! -d "${ANDROID_SDK_ROOT}" ]]; then
+    local ANDROID_SDK_ROOT="${CHROME_SRC}/third_party/android_tools/sdk/"
+  fi
+
+  # Add Android SDK tools to system path.
+  export PATH=$PATH:${ANDROID_SDK_ROOT}/platform-tools
+
+  # Add Android utility tools to the system path.
+  export PATH=$PATH:${ANDROID_SDK_ROOT}/tools/
+
+  # Add Chromium Android development scripts to system path.
+  # Must be after CHROME_SRC is set.
+  export PATH=$PATH:${CHROME_SRC}/build/android
+
+  export ENVSETUP_GYP_CHROME_SRC=${CHROME_SRC}  # TODO(thakis): Remove.
+}
+# In zsh, $0 is the name of the file being sourced.
+android_envsetup_main "${BASH_SOURCE:-$0}"
+unset -f android_envsetup_main
+
+android_gyp() {
+  echo "Please call build/gyp_chromium instead. android_gyp is going away."
+  "${ENVSETUP_GYP_CHROME_SRC}/build/gyp_chromium" --depth="${ENVSETUP_GYP_CHROME_SRC}" --check "$@"
+}