Added HTTP endpoints for Correctness counts

golden/go/expstorage/sqlexpstore.go

Index: golden/go/expstorage/sqlexpstore.go
diff --git a/golden/go/expstorage/sqlexpstore.go b/golden/go/expstorage/sqlexpstore.go
index 845e4a90d450cb23b3283a77abfa1a779977b5af..75d6571f684a9dd16578f217546f4eceeaee6b8f 100644
--- a/golden/go/expstorage/sqlexpstore.go
+++ b/golden/go/expstorage/sqlexpstore.go
@@ -1,6 +1,7 @@
 package expstorage
 
 import (
+	"database/sql"
 	"encoding/json"
 
 	"skia.googlesource.com/buildbot.git/go/database"
@@ -26,8 +27,13 @@ func (e *SQLExpectationsStore) Get(modifiable bool) (exp *Expectations, err erro
 	         ORDER BY ts DESC
 	         LIMIT 1`
 
+	// Read the expectations. If there are no rows, that means we have no
+	// expectations yet.
 	var expJSON string
-	if err := e.vdb.DB.QueryRow(stmt).Scan(&expJSON); err != nil {
+	switch err := e.vdb.DB.QueryRow(stmt).Scan(&expJSON); {
+	case err == sql.ErrNoRows:
+		return NewExpectations(modifiable), nil
+	case err != nil:
 		return nil, err
 	}