Limit editing HTML source for rich text editor field in Sitecore

I recently get a requirement about limiting the way of editing ram html in Rich Tex Editor. After a few digging around the Sitecore, here is how I figured.

There are two places in Rich Text editor you can change the html markup in Content Editor.

1st place

2nd place

For 1st place, goes to Core database "/sitecore/system/Field types/Simple Types/Rich Text" and in "Security Editor" to deny "read" for both items as highlighted for the "Sitecore Roles" you prefer.

For 2nd place, it is a bit of tricky. We first need to find out what is our default profile is by going to web.config.

<setting name="HtmlEditor.DefaultProfile" value="/sitecore/system/Settings/Html Editor Profiles/Rich Text Default" />

After that, we located this profile in "Core" database and locate 

"/sitecore/system/Settings/Html Editor Profiles/Rich Text Default/Buttons/HTML View"

So we need to do the same by deny "read" from "Security editor" for certain roles as well.

Done!