Revert "Revert "Merge branch 'master' of https://github.com/discourse/discourse""

This reverts commit 20780a1eeed56b321daf18ee6bbfe681a51d1bf4.

* SECURITY: re-adds accidentally reverted commit:
  03d26cd6: ensure embed_url contains valid http(s) uri
* when the merge commit e62a85cf was reverted, git chose the 2660c2e2 parent to land on
  instead of the 03d26cd6 parent (which contains security fixes)

spec/requests/about_controller_spec.rb

@@ -36,5 +36,21 @@ describe AboutController do
         expect(response.body).to include("<title>About - Discourse</title>")
       end
     end
+
+    it "serializes stats when 'Guardian#can_see_about_stats?' is true" do
+      Guardian.any_instance.stubs(:can_see_about_stats?).returns(true)
+      get "/about.json"
+
+      expect(response.status).to eq(200)
+      expect(response.parsed_body["about"].keys).to include("stats")
+    end
+
+    it "does not serialize stats when 'Guardian#can_see_about_stats?' is false" do
+      Guardian.any_instance.stubs(:can_see_about_stats?).returns(false)
+      get "/about.json"
+
+      expect(response.status).to eq(200)
+      expect(response.parsed_body["about"].keys).not_to include("stats")
+    end
   end
 end