The links from Google Results page to your site are not simple links. If you look closely you'll notice that the link pass through javascript and a redirect before actually reaching your site.
Google does that for measuring the click through of organic results page on their end and also to pass a referral so marketers can attribute those visits back to Google Search.
Google does take privacy into consideration and doesn't pass along the actual query the user searched for. That's why you can't see the keyword in Google, instead it says (not provided).
Previously, when some Google searches were through HTTP Google used to pass the query along, that doesn't happen anymore as 100% of the searches are now through HTTPS.
So to answer your question: Yes, the spec require browsers to not pass referrals while on HTTPS and all browsers follow that, but Google uses some custom JS and redirects to pass a referral anyway.
UPDATE
In Google's case the redirect lives on www.google.com/url
Here's the code on that page for reference, the code has been modified for clarification:
<script>
window.googleJavaScriptRedirect=1
</script>
<META name="referrer" content="origin">
<script>
var m = {
navigateTo:function(b,a,d){
if(b!=a&&b.google){
if(b.google.r{
b.google.r=0;
b.location.href=d;
a.location.replace("about:blank");
}
} else {
a.location.replace(d);
}
}
};
m.navigateTo(
window.parent,
window,
"http://www.cutestpaw.com/articles/50-cute-puppies-make-your-girlfriend-smile/"
);
</script>
<noscript>
<META http-equiv="refresh" content="0;URL='http://www.cutestpaw.com/articles/50-cute-puppies-make-your-girlfriend-smile/'">
</noscript>
You can see that it includes a Meta name="referral" that is used to pass referral information. Origin is actually a HTTP parameter passed to the request of google.com/url.
