UserAgent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_3) AppleWebKit/602.4.8 (KHTML, like Gecko) Version/10.0.3 Safari/602.4.8

Example URL:
https://developer.google.com/speed/webp/gallery1

Steps to reproduce the problem:
1. Download Yoink for Mac (from http://eternalstorms.at/yoink)
2. Navigate to the URL above
3. Try to drag a WebP image to Yoink

What is the expected behavior?
The WebP image gets added to Yoink, just like JPEGs, PNGs and any other type of image file on the web

What went wrong?
The WebP image is not a "promise-file-drag" like JPEGs or PNGs in Chrome, so Yoink (and the Finder, by the way) can not accept those drags.

Please implement the same file-promise-drag-operation for WebP images in Chrome which you already have for JPEGs, PNGs, GIFs, etc.

Does it occur on multiple sites: Yes

Is it a problem with a plugin? No 

Did this work before? No 

Does this work in other browsers? Yes

Chrome version: 57.0  Channel: stable
OS Version: OS X 10.12.3
Flash Version: