editor/build/build.py: Use 32-bit version of dartium/content_shell on macos/windows + bat script fi…

dart/tools/dartium/download_shellscript_template.bat

Index: dart/tools/dartium/download_shellscript_template.bat
diff --git a/dart/tools/dartium/download_shellscript_template.bat b/dart/tools/dartium/download_shellscript_template.bat
index 8171bcd830a883ebb911dd687829492c22529ca5..bf8183280c02a02eadbafd6741e645075c31d477 100644
--- a/dart/tools/dartium/download_shellscript_template.bat
+++ b/dart/tools/dartium/download_shellscript_template.bat
@@ -1,14 +1,16 @@
-REM Copyright (c) 2013, the Dart project authors. Please see the AUTHORS file
-REM for details. All rights reserved. Use of this source code is governed by a
-REM BSD-style license that can be found in the LICENSE file.
+@REM Copyright (c) 2013, the Dart project authors. Please see the AUTHORS file
+@REM for details. All rights reserved. Use of this source code is governed by a
+@REM BSD-style license that can be found in the LICENSE file.
 
-REM This script will download VAR_DOWNLOAD_URL to VAR_DESTINATION in the current
-REM working directory.
+@REM This script will download VAR_DOWNLOAD_URL to VAR_DESTINATION in the
+@REM current working directory.
 
-CHROMIUM_DIR="%~dp0"
-SDK_BIN="%CHROMIUM_DIR%\..\dart-sdk\bin"
+@echo off
 
-DART="%SDK_BIN%\dart.exe"
-DOWNLOAD_SCRIPT="%CHROMIUM_DIR%\download_file.dart"
+set "CHROMIUM_DIR=%~dp0"
+set "SDK_BIN=%CHROMIUM_DIR%\..\dart-sdk\bin"
+
+set "DART=%SDK_BIN%\dart.exe"
+set "DOWNLOAD_SCRIPT=%CHROMIUM_DIR%\download_file.dart"
 
 "%DART%" "%DOWNLOAD_SCRIPT%" "VAR_DOWNLOAD_URL" "VAR_DESTINATION"