Chrome Extension Manifest ‘Matches’

You need to surround the value of the content_scripts field in square brackets:

"content_scripts": [ {
  "matches": ["http://*"],
  "js": ["scripts.js"]
} ]

(see the Chrome Docs for more info)

Incidentally, using http://*/* would be a better match for all urls (see the docs), adding https://*/* if you also need to match those as well.

Edit:

Following your edit, the error you are getting is because of the match pattern being incorrect.