Adds support for JSON and style module types as <link rel="modulepreload"> destinations. <link rel="modulepreload"> is already supported in Chromium (see https://chromestatus.com/feature/5762805915451392), but it currently only supports preloading script-like module scripts. This feature addresses a functionality gap, as JSON and CSS module scripts are supported in Chromium elsewhere but are not supported as <link rel="modulepreload"> destinations. Style modules can be preloaded with <link rel="modulepreload" as="style" href="..."> and JSON modules can be preloaded with <link rel="modulepreload" as="json" href="...">.
Style and JSON are fully supported as modules in Chromium (see https://chromestatus.com/feature/5948572598009856 and https://chromestatus.com/feature/5749863620804608), but <link rel=modulepreload> only supports preloading script modules. This feature addresses a gap in the platform. In addition, supporting "style" as a modulepreload destination addresses a pain point identified when using external files with Declarative CSS Modules (see https://chromestatus.com/feature/4790543041298432).