Change text/font case ANYWHERE including chrome input fields
I think what you're asking for is a context menu (i.e. right-click) service that will allow you to toggle text case, yes? 

If so, what I use for that purpose is a bit of freeware from DEVONTechnologies called WordService. They describe it, thusly:  


  WordService
  
  WordService provides a large number of commands for working with selected text. Extend your favorite word processor, email app, or web browser e.g. with functions for reformating text paragraphs, cleaning up tabs, quotes, or line endings. Remove unwanted text parts, sort lines or paragraphs, change case, and do much, much more with text.  


The services install to System Preferences -> Keyboard -> Shortcuts -> Services -> Text and you can toggle the ones you want/don't want on/off and set key command shortcuts for them.  






In the right-click menu, the services will appear similarly to the below (minus my additional services):

  

And will easily let you transform text field input:


  

You can download WordService, either, directly from DEVONTechnologies' site or from the Mac App Store and it is also available via the homebrew command: brew cask install wordservice.