UserAgent: Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/70.0.3538.77 Safari/537.36

Steps to reproduce the problem:
Hi, I am developing a web-app https://www.Photopea.com and many users are complaining about not being able to do some stuff, they were used to do in their previous native programs.

I think we should make a single Permission, which will be asked from the user only once, and will unlock a whole set of possibilities to a webapp. We could call it a "Native Permission".

There are three things that native apps can do, and I need to do them Photopea (and all my users want Photopea to do them):
- prevent the native behaviour of any keyboard shortcut (Ctrl+T, Ctrl+W, ...)
- read the Clipboard content / initiate Pasting without the explicit pasting (to make a custom Paste button)
- preserve a link to a file, opened from a local filesystem, and rewrite that file without a Save As dialog (to implement File - Save).

These rights could be placed under one "Native" permission. We could even put the Fullscreen API, Mouse Lock API or access to a mic and a camera under this (to not bother users with multiple requests for permissions).

As the first step, we could create a "Native permission", whose request would be initiated by a website, and confirming it would allow a webapp to prevent all keyboard shortcuts.

It would be nice to prevent Ctrl+Click as Rigth Click (on Mac OS) or Spacebar+Click as Right Click (on Chrome OS).

What is the expected behavior?

What went wrong?
Web apps are being kept less powerful next to native apps, and it is done on purpose by browser makers :(

Did this work before? N/A 

Chrome version: 70.0.3538.77  Channel: stable
OS Version: 6.1 (Windows 7, Windows Server 2008 R2)
Flash Version: