AFAIK, command-W is a Microsoft invention. They introduced it in Word, Excel and IE for the Mac, then copied it to Office for Windows. Apple adopted it in its UI guidelines.
The "Apple Human Interface Guidelines" (1987) surely doesn't mention it (it has undo/cut/copy/paste, new/open/save, cancel and help, and plain/bold/italic/underline)
"Windows User Experience" (1999) doesn't mention it, either.
"OS X Human Interface Guidelines" (2015) does mention it (aside: I find it good to see that the online version already has a section on the Touch Bar (https://developer.apple.com/library/content/documentation/Us...). It also has a new name: macOS Human Interface Guidelines)
No, it doesn't. Ctrl+W isn't a general shortcut on Windows. A number of programs have adopted it to close windows/tabs (seems to have risen to prominence after browsers started binding it), but it's not a standard binding still. e.g. It does nothing in Outlook or Notepad.
https://support.microsoft.com/en-us/help/12445/windows-keybo...