You can't upload through Cloudfront. It's a good analogy though, you can think of this feature as a "CDN for uploads", if you'll excuse the abuse of the CDN acronym.
"You can use existing Amazon CloudFront distributions for upload requests by simply enabling support in the AWS management console. When end users upload content, CloudFront will send the upload request back to the origin web server (such as an Amazon S3 bucket, an Amazon EC2 instance, an Elastic Load Balancer, or your own origin server) over an optimized route that uses persistent connections, TCP/IP and network path optimizations."
I stand corrected, thanks for the info. Cloudfront doesn't appear to support multi-part uploads however, which I guess is the primary value-add of the newly announced service.
That gets less important each passing year as connections get faster, even on mobile. I agree you can't restart uploads though without multi part support.
https://aws.amazon.com/about-aws/whats-new/2013/10/15/amazon...
"You can use existing Amazon CloudFront distributions for upload requests by simply enabling support in the AWS management console. When end users upload content, CloudFront will send the upload request back to the origin web server (such as an Amazon S3 bucket, an Amazon EC2 instance, an Elastic Load Balancer, or your own origin server) over an optimized route that uses persistent connections, TCP/IP and network path optimizations."