Upload widget not working on android / gmail webview

We're having trouble with the upload widget. It's embedded in a webpage, which is linked in an email.

- User clicks link in email in the Gmail app on Android. Gmail opens webpage in a webview. 

- User clicks link on a page. Upload widget loads properly, camera opens properly. 

- User takes photo and clicks "OK". Nothing happens. 

This only happens in an android webview: 

- No issues on Chrome browser on Android

- No issues on Gmail app on iOS

Any suggestions?