Even when css3d is added to the requirements in manifest.json, CSS renders in 2d inside of a <webview>. Is this a known issue? Is webgl not supported in <webview> as well?
See the issue in aschwartz/chrome-chromeless for more information.
3D CSS renders in webviews, try out https://github.com/GoogleChrome/chrome-app-samples/tree/master/webview-samples/browser
Thanks. It looks like some of the issues with <webview> resizing are fixed as well.