all: revert "all: prefer strings.IndexByte over strings.Index"

This reverts https://golang.org/cl/65930.

Fixes #22148

Change-Id: Ie0712621ed89c43bef94417fc32de9af77607760
Reviewed-on: https://go-review.googlesource.com/68430
Reviewed-by: Ian Lance Taylor <iant@golang.org>

3 files changed, 4 insertions, 4 deletions

diff --git a/src/encoding/json/tags.go b/src/encoding/json/tags.go
index 6a8d03a5df..c38fd5102f 100644
--- a/src/encoding/json/tags.go
+++ b/src/encoding/json/tags.go
@@ -15,7 +15,7 @@ type tagOptions string
 // parseTag splits a struct field's json tag into its name and
 // comma-separated options.
 func parseTag(tag string) (string, tagOptions) {
-	if idx := strings.IndexByte(tag, ','); idx != -1 {
+	if idx := strings.Index(tag, ","); idx != -1 {
 		return tag[:idx], tagOptions(tag[idx+1:])
 	}
 	return tag, tagOptions("")
@@ -31,7 +31,7 @@ func (o tagOptions) Contains(optionName string) bool {
 	s := string(o)
 	for s != "" {
 		var next string
-		i := strings.IndexByte(s, ',')
+		i := strings.Index(s, ",")
 		if i >= 0 {
 			s, next = s[:i], s[i+1:]
 		}
diff --git a/src/encoding/xml/typeinfo.go b/src/encoding/xml/typeinfo.go
index b3346d304e..2e7ae935a8 100644
--- a/src/encoding/xml/typeinfo.go
+++ b/src/encoding/xml/typeinfo.go
@@ -115,7 +115,7 @@ func structFieldInfo(typ reflect.Type, f *reflect.StructField) (*fieldInfo, erro
 
 	// Split the tag from the xml namespace if necessary.
 	tag := f.Tag.Get("xml")
-	if i := strings.IndexByte(tag, ' '); i >= 0 {
+	if i := strings.Index(tag, " "); i >= 0 {
 		finfo.xmlns, tag = tag[:i], tag[i+1:]
 	}
 
diff --git a/src/encoding/xml/xml.go b/src/encoding/xml/xml.go
index 27b871649b..be90b62c9a 100644
--- a/src/encoding/xml/xml.go
+++ b/src/encoding/xml/xml.go
@@ -1161,7 +1161,7 @@ func (d *Decoder) nsname() (name Name, ok bool) {
 	if !ok {
 		return
 	}
-	i := strings.IndexByte(s, ':')
+	i := strings.Index(s, ":")
 	if i < 0 {
 		name.Local = s
 	} else {