Make StringPiece to be std::string_view alias

Bug: 237583012
Test: build + boot + UTs

Change-Id: I849831f4466d3b9c7ec842b75256e7fcba77a0c0
diff --git a/tools/aapt2/xml/XmlPullParser.cpp b/tools/aapt2/xml/XmlPullParser.cpp
index bfa0749..d79446b 100644
--- a/tools/aapt2/xml/XmlPullParser.cpp
+++ b/tools/aapt2/xml/XmlPullParser.cpp
@@ -140,8 +140,7 @@
   return event_queue_.front().data2;
 }
 
-std::optional<ExtractedPackage> XmlPullParser::TransformPackageAlias(
-    const StringPiece& alias) const {
+std::optional<ExtractedPackage> XmlPullParser::TransformPackageAlias(StringPiece alias) const {
   if (alias.empty()) {
     return ExtractedPackage{{}, false /*private*/};
   }
@@ -307,7 +306,7 @@
                                       parser->depth_ });
 }
 
-std::optional<StringPiece> FindAttribute(const XmlPullParser* parser, const StringPiece& name) {
+std::optional<StringPiece> FindAttribute(const XmlPullParser* parser, StringPiece name) {
   auto iter = parser->FindAttribute("", name);
   if (iter != parser->end_attributes()) {
     return StringPiece(util::TrimWhitespace(iter->value));
@@ -315,8 +314,7 @@
   return {};
 }
 
-std::optional<StringPiece> FindNonEmptyAttribute(const XmlPullParser* parser,
-                                                 const StringPiece& name) {
+std::optional<StringPiece> FindNonEmptyAttribute(const XmlPullParser* parser, StringPiece name) {
   auto iter = parser->FindAttribute("", name);
   if (iter != parser->end_attributes()) {
     StringPiece trimmed = util::TrimWhitespace(iter->value);