9549a0fbe2
* Roll esbuild as a CIPD package along with the browser roller. I renamed `browser_lock`/`browser_roller` etc to `package_lock` and `package_roller` since it will handle more than just browsers now. * Download the esbuild CIPD package via DEPS. * Have a build rule for running esbuild on some JavaScript or TypeScript * Bundle and minify `flutter.js` using esbuild. * Include in `flutter_web_sdk` the original `flutter.js` source, the minified `flutter.js`, and a sourcemap file to map between thnm. * Also slightly changed the structure to put the `flutter.js` stuff in `flutter_web_sdk/flutter_js` instead of just at the root level of `flutter_web_sdk`. This should be fine because I haven't merged the change that has the flutter tool consume this yet.