65e8ec2140
1. Change chromium default branch from master (404) to main. 2. When I migrated the template to ARC is triggered a `-Wobjc-redundant-literal-use` error, so fix that. Engine PR is https://github.com/flutter/engine/pull/51981 3. Update to `FLUTTER_SHELL_PLATFORM_EMBEDDER_TEST_UTILS_KEY_CODES_G_H_` to match https://github.com/flutter/engine/pull/49006 This only updates the template and the script--I ran the script to validate it worked and built in the engine, but did not check in the actual generated key code changes (filed https://github.com/flutter/flutter/issues/146480 for that).