WebSQL was replaced as a specification by IndexedDB, and Mozilla and Microsoft publicly opposed implementing it. Google has said in the past that they have no plans to remove it from Chrome, although given that they're shutting down Google+ due to vulnerabilities, I am curious if they are going to change their minds.
They are shutting down Google+ because no one uses it and they don't want to spend any money on developers maintaining a pointless product...
I think the Google+ shutdown has more to do with the G+ data leaks and increased scrutiny social media platforms are coming under because of fake news and fb political issues.
Perfect scapegoat to sunset a product that one one uses.
You cant even disable it, its like Google really really wants it present on every computer out there. What one could do is write an extension to stub it out.
Work on the specification stopped in 2010 but it's not been removed from the browsers that supported it.