diff --git a/tools/aapt2/util/Files.cpp b/tools/aapt2/util/Files.cpp
index 5d5b7cd..93c1b61 100644
--- a/tools/aapt2/util/Files.cpp
+++ b/tools/aapt2/util/Files.cpp
@@ -139,7 +139,7 @@
   return ::android::base::utf8::mkdir(path.c_str(), mode) == 0 || errno == EEXIST;
 }
 
-StringPiece GetStem(const StringPiece& path) {
+StringPiece GetStem(StringPiece path) {
   const char* start = path.begin();
   const char* end = path.end();
   for (const char* current = end - 1; current != start - 1; --current) {
@@ -150,7 +150,7 @@
   return {};
 }
 
-StringPiece GetFilename(const StringPiece& path) {
+StringPiece GetFilename(StringPiece path) {
   const char* end = path.end();
   const char* last_dir_sep = path.begin();
   for (const char* c = path.begin(); c != end; ++c) {
@@ -161,7 +161,7 @@
   return StringPiece(last_dir_sep, end - last_dir_sep);
 }
 
-StringPiece GetExtension(const StringPiece& path) {
+StringPiece GetExtension(StringPiece path) {
   StringPiece filename = GetFilename(path);
   const char* const end = filename.end();
   const char* c = std::find(filename.begin(), end, '.');
@@ -171,7 +171,7 @@
   return {};
 }
 
-bool IsHidden(const android::StringPiece& path) {
+bool IsHidden(android::StringPiece path) {
   return util::StartsWith(GetFilename(path), ".");
 }
 
@@ -193,16 +193,16 @@
   if (args.empty()) {
     return "";
   }
-  std::string out = args[0].to_string();
+  std::string out{args[0]};
   for (int i = 1; i < args.size(); i++) {
     file::AppendPath(&out, args[i]);
   }
   return out;
 }
 
-std::string PackageToPath(const StringPiece& package) {
+std::string PackageToPath(StringPiece package) {
   std::string out_path;
-  for (const StringPiece& part : util::Tokenize(package, '.')) {
+  for (StringPiece part : util::Tokenize(package, '.')) {
     AppendPath(&out_path, part);
   }
   return out_path;
@@ -241,10 +241,10 @@
   return std::move(filemap);
 }
 
-bool AppendArgsFromFile(const StringPiece& path, std::vector<std::string>* out_arglist,
+bool AppendArgsFromFile(StringPiece path, std::vector<std::string>* out_arglist,
                         std::string* out_error) {
   std::string contents;
-  if (!ReadFileToString(path.to_string(), &contents, true /*follow_symlinks*/)) {
+  if (!ReadFileToString(std::string(path), &contents, true /*follow_symlinks*/)) {
     if (out_error) {
       *out_error = "failed to read argument-list file";
     }
@@ -254,16 +254,16 @@
   for (StringPiece line : util::Tokenize(contents, ' ')) {
     line = util::TrimWhitespace(line);
     if (!line.empty()) {
-      out_arglist->push_back(line.to_string());
+      out_arglist->emplace_back(line);
     }
   }
   return true;
 }
 
-bool AppendSetArgsFromFile(const StringPiece& path, std::unordered_set<std::string>* out_argset,
+bool AppendSetArgsFromFile(StringPiece path, std::unordered_set<std::string>* out_argset,
                            std::string* out_error) {
   std::string contents;
-  if(!ReadFileToString(path.to_string(), &contents, true /*follow_symlinks*/)) {
+  if (!ReadFileToString(std::string(path), &contents, true /*follow_symlinks*/)) {
     if (out_error) {
       *out_error = "failed to read argument-list file";
     }
@@ -273,13 +273,13 @@
   for (StringPiece line : util::Tokenize(contents, ' ')) {
     line = util::TrimWhitespace(line);
     if (!line.empty()) {
-      out_argset->insert(line.to_string());
+      out_argset->emplace(line);
     }
   }
   return true;
 }
 
-bool FileFilter::SetPattern(const StringPiece& pattern) {
+bool FileFilter::SetPattern(StringPiece pattern) {
   pattern_tokens_ = util::SplitAndLowercase(pattern, ':');
   return true;
 }
@@ -343,10 +343,10 @@
   return true;
 }
 
-std::optional<std::vector<std::string>> FindFiles(const android::StringPiece& path,
+std::optional<std::vector<std::string>> FindFiles(android::StringPiece path,
                                                   android::IDiagnostics* diag,
                                                   const FileFilter* filter) {
-  const std::string root_dir = path.to_string();
+  const auto& root_dir = path;
   std::unique_ptr<DIR, decltype(closedir)*> d(opendir(root_dir.data()), closedir);
   if (!d) {
     diag->Error(android::DiagMessage() << SystemErrorCodeToString(errno) << ": " << root_dir);
@@ -361,7 +361,7 @@
     }
 
     std::string file_name = entry->d_name;
-    std::string full_path = root_dir;
+    std::string full_path{root_dir};
     AppendPath(&full_path, file_name);
     const FileType file_type = GetFileType(full_path);
 
@@ -380,7 +380,7 @@
 
   // Now process subdirs.
   for (const std::string& subdir : subdirs) {
-    std::string full_subdir = root_dir;
+    std::string full_subdir{root_dir};
     AppendPath(&full_subdir, subdir);
     std::optional<std::vector<std::string>> subfiles = FindFiles(full_subdir, diag, filter);
     if (!subfiles) {
diff --git a/tools/aapt2/util/Files.h b/tools/aapt2/util/Files.h
index ee95712..42eeaf2 100644
--- a/tools/aapt2/util/Files.h
+++ b/tools/aapt2/util/Files.h
@@ -66,31 +66,31 @@
 bool mkdirs(const std::string& path);
 
 // Returns all but the last part of the path.
-android::StringPiece GetStem(const android::StringPiece& path);
+android::StringPiece GetStem(android::StringPiece path);
 
 // Returns the last part of the path with extension.
-android::StringPiece GetFilename(const android::StringPiece& path);
+android::StringPiece GetFilename(android::StringPiece path);
 
 // Returns the extension of the path. This is the entire string after the first '.' of the last part
 // of the path.
-android::StringPiece GetExtension(const android::StringPiece& path);
+android::StringPiece GetExtension(android::StringPiece path);
 
 // Returns whether or not the name of the file or directory is a hidden file name
-bool IsHidden(const android::StringPiece& path);
+bool IsHidden(android::StringPiece path);
 
 // Converts a package name (com.android.app) to a path: com/android/app
-std::string PackageToPath(const android::StringPiece& package);
+std::string PackageToPath(android::StringPiece package);
 
 // Creates a FileMap for the file at path.
 std::optional<android::FileMap> MmapPath(const std::string& path, std::string* out_error);
 
 // Reads the file at path and appends each line to the outArgList vector.
-bool AppendArgsFromFile(const android::StringPiece& path, std::vector<std::string>* out_arglist,
+bool AppendArgsFromFile(android::StringPiece path, std::vector<std::string>* out_arglist,
                         std::string* out_error);
 
 // Reads the file at path and appends each line to the outargset set.
-bool AppendSetArgsFromFile(const android::StringPiece& path,
-                        std::unordered_set<std::string>* out_argset, std::string* out_error);
+bool AppendSetArgsFromFile(android::StringPiece path, std::unordered_set<std::string>* out_argset,
+                           std::string* out_error);
 
 // Filter that determines which resource files/directories are
 // processed by AAPT. Takes a pattern string supplied by the user.
@@ -112,7 +112,7 @@
   // - The special filenames "." and ".." are always ignored.
   // - Otherwise the full string is matched.
   // - match is not case-sensitive.
-  bool SetPattern(const android::StringPiece& pattern);
+  bool SetPattern(android::StringPiece pattern);
 
   // Applies the filter, returning true for pass, false for fail.
   bool operator()(const std::string& filename, FileType type) const;
@@ -126,7 +126,7 @@
 
 // Returns a list of files relative to the directory identified by `path`.
 // An optional FileFilter filters out any files that don't pass.
-std::optional<std::vector<std::string>> FindFiles(const android::StringPiece& path,
+std::optional<std::vector<std::string>> FindFiles(android::StringPiece path,
                                                   android::IDiagnostics* diag,
                                                   const FileFilter* filter = nullptr);
 
diff --git a/tools/aapt2/util/Util.cpp b/tools/aapt2/util/Util.cpp
index 9b7ebdd..be87766 100644
--- a/tools/aapt2/util/Util.cpp
+++ b/tools/aapt2/util/Util.cpp
@@ -43,15 +43,14 @@
 // See frameworks/base/core/java/android/content/pm/parsing/ParsingPackageUtils.java
 constexpr static const size_t kMaxPackageNameSize = 223;
 
-static std::vector<std::string> SplitAndTransform(
-    const StringPiece& str, char sep, const std::function<char(char)>& f) {
+static std::vector<std::string> SplitAndTransform(StringPiece str, char sep, char (*f)(char)) {
   std::vector<std::string> parts;
   const StringPiece::const_iterator end = std::end(str);
   StringPiece::const_iterator start = std::begin(str);
   StringPiece::const_iterator current;
   do {
     current = std::find(start, end, sep);
-    parts.emplace_back(str.substr(start, current).to_string());
+    parts.emplace_back(start, current);
     if (f) {
       std::string& part = parts.back();
       std::transform(part.begin(), part.end(), part.begin(), f);
@@ -61,29 +60,29 @@
   return parts;
 }
 
-std::vector<std::string> Split(const StringPiece& str, char sep) {
+std::vector<std::string> Split(StringPiece str, char sep) {
   return SplitAndTransform(str, sep, nullptr);
 }
 
-std::vector<std::string> SplitAndLowercase(const StringPiece& str, char sep) {
-  return SplitAndTransform(str, sep, ::tolower);
+std::vector<std::string> SplitAndLowercase(StringPiece str, char sep) {
+  return SplitAndTransform(str, sep, [](char c) -> char { return ::tolower(c); });
 }
 
-bool StartsWith(const StringPiece& str, const StringPiece& prefix) {
+bool StartsWith(StringPiece str, StringPiece prefix) {
   if (str.size() < prefix.size()) {
     return false;
   }
   return str.substr(0, prefix.size()) == prefix;
 }
 
-bool EndsWith(const StringPiece& str, const StringPiece& suffix) {
+bool EndsWith(StringPiece str, StringPiece suffix) {
   if (str.size() < suffix.size()) {
     return false;
   }
   return str.substr(str.size() - suffix.size(), suffix.size()) == suffix;
 }
 
-StringPiece TrimLeadingWhitespace(const StringPiece& str) {
+StringPiece TrimLeadingWhitespace(StringPiece str) {
   if (str.size() == 0 || str.data() == nullptr) {
     return str;
   }
@@ -97,7 +96,7 @@
   return StringPiece(start, end - start);
 }
 
-StringPiece TrimTrailingWhitespace(const StringPiece& str) {
+StringPiece TrimTrailingWhitespace(StringPiece str) {
   if (str.size() == 0 || str.data() == nullptr) {
     return str;
   }
@@ -111,7 +110,7 @@
   return StringPiece(start, end - start);
 }
 
-StringPiece TrimWhitespace(const StringPiece& str) {
+StringPiece TrimWhitespace(StringPiece str) {
   if (str.size() == 0 || str.data() == nullptr) {
     return str;
   }
@@ -130,9 +129,9 @@
   return StringPiece(start, end - start);
 }
 
-static int IsJavaNameImpl(const StringPiece& str) {
+static int IsJavaNameImpl(StringPiece str) {
   int pieces = 0;
-  for (const StringPiece& piece : Tokenize(str, '.')) {
+  for (StringPiece piece : Tokenize(str, '.')) {
     pieces++;
     if (!text::IsJavaIdentifier(piece)) {
       return -1;
@@ -141,17 +140,17 @@
   return pieces;
 }
 
-bool IsJavaClassName(const StringPiece& str) {
+bool IsJavaClassName(StringPiece str) {
   return IsJavaNameImpl(str) >= 2;
 }
 
-bool IsJavaPackageName(const StringPiece& str) {
+bool IsJavaPackageName(StringPiece str) {
   return IsJavaNameImpl(str) >= 1;
 }
 
-static int IsAndroidNameImpl(const StringPiece& str) {
+static int IsAndroidNameImpl(StringPiece str) {
   int pieces = 0;
-  for (const StringPiece& piece : Tokenize(str, '.')) {
+  for (StringPiece piece : Tokenize(str, '.')) {
     if (piece.empty()) {
       return -1;
     }
@@ -173,15 +172,14 @@
   return pieces;
 }
 
-bool IsAndroidPackageName(const StringPiece& str) {
+bool IsAndroidPackageName(StringPiece str) {
   if (str.size() > kMaxPackageNameSize) {
     return false;
   }
   return IsAndroidNameImpl(str) > 1 || str == "android";
 }
 
-bool IsAndroidSharedUserId(const android::StringPiece& package_name,
-                           const android::StringPiece& shared_user_id) {
+bool IsAndroidSharedUserId(android::StringPiece package_name, android::StringPiece shared_user_id) {
   if (shared_user_id.size() > kMaxPackageNameSize) {
     return false;
   }
@@ -189,25 +187,24 @@
          package_name == "android";
 }
 
-bool IsAndroidSplitName(const StringPiece& str) {
+bool IsAndroidSplitName(StringPiece str) {
   return IsAndroidNameImpl(str) > 0;
 }
 
-std::optional<std::string> GetFullyQualifiedClassName(const StringPiece& package,
-                                                      const StringPiece& classname) {
+std::optional<std::string> GetFullyQualifiedClassName(StringPiece package, StringPiece classname) {
   if (classname.empty()) {
     return {};
   }
 
   if (util::IsJavaClassName(classname)) {
-    return classname.to_string();
+    return std::string(classname);
   }
 
   if (package.empty()) {
     return {};
   }
 
-  std::string result = package.to_string();
+  std::string result{package};
   if (classname.data()[0] != '.') {
     result += '.';
   }
@@ -251,7 +248,7 @@
   return static_cast<size_t>(c - start);
 }
 
-bool VerifyJavaStringFormat(const StringPiece& str) {
+bool VerifyJavaStringFormat(StringPiece str) {
   const char* c = str.begin();
   const char* const end = str.end();
 
@@ -341,7 +338,7 @@
   return true;
 }
 
-std::u16string Utf8ToUtf16(const StringPiece& utf8) {
+std::u16string Utf8ToUtf16(StringPiece utf8) {
   ssize_t utf16_length = utf8_to_utf16_length(
       reinterpret_cast<const uint8_t*>(utf8.data()), utf8.length());
   if (utf16_length <= 0) {
@@ -381,7 +378,7 @@
   const char* end = str_.end();
   if (start == end) {
     end_ = true;
-    token_.assign(token_.end(), 0);
+    token_ = StringPiece(token_.end(), 0);
     return *this;
   }
 
@@ -389,12 +386,12 @@
   const char* current = start;
   while (current != end) {
     if (*current == separator_) {
-      token_.assign(start, current - start);
+      token_ = StringPiece(start, current - start);
       return *this;
     }
     ++current;
   }
-  token_.assign(start, end - start);
+  token_ = StringPiece(start, end - start);
   return *this;
 }
 
@@ -409,15 +406,17 @@
   return !(*this == rhs);
 }
 
-Tokenizer::iterator::iterator(const StringPiece& s, char sep, const StringPiece& tok, bool end)
-    : str_(s), separator_(sep), token_(tok), end_(end) {}
+Tokenizer::iterator::iterator(StringPiece s, char sep, StringPiece tok, bool end)
+    : str_(s), separator_(sep), token_(tok), end_(end) {
+}
 
-Tokenizer::Tokenizer(const StringPiece& str, char sep)
+Tokenizer::Tokenizer(StringPiece str, char sep)
     : begin_(++iterator(str, sep, StringPiece(str.begin() - 1, 0), false)),
-      end_(str, sep, StringPiece(str.end(), 0), true) {}
+      end_(str, sep, StringPiece(str.end(), 0), true) {
+}
 
-bool ExtractResFilePathParts(const StringPiece& path, StringPiece* out_prefix,
-                             StringPiece* out_entry, StringPiece* out_suffix) {
+bool ExtractResFilePathParts(StringPiece path, StringPiece* out_prefix, StringPiece* out_entry,
+                             StringPiece* out_suffix) {
   const StringPiece res_prefix("res/");
   if (!StartsWith(path, res_prefix)) {
     return false;
diff --git a/tools/aapt2/util/Util.h b/tools/aapt2/util/Util.h
index 8d3b413..40ff5b6 100644
--- a/tools/aapt2/util/Util.h
+++ b/tools/aapt2/util/Util.h
@@ -48,44 +48,44 @@
   T end;
 };
 
-std::vector<std::string> Split(const android::StringPiece& str, char sep);
-std::vector<std::string> SplitAndLowercase(const android::StringPiece& str, char sep);
+std::vector<std::string> Split(android::StringPiece str, char sep);
+std::vector<std::string> SplitAndLowercase(android::StringPiece str, char sep);
 
 // Returns true if the string starts with prefix.
-bool StartsWith(const android::StringPiece& str, const android::StringPiece& prefix);
+bool StartsWith(android::StringPiece str, android::StringPiece prefix);
 
 // Returns true if the string ends with suffix.
-bool EndsWith(const android::StringPiece& str, const android::StringPiece& suffix);
+bool EndsWith(android::StringPiece str, android::StringPiece suffix);
 
 // Creates a new StringPiece that points to a substring of the original string without leading
 // whitespace.
-android::StringPiece TrimLeadingWhitespace(const android::StringPiece& str);
+android::StringPiece TrimLeadingWhitespace(android::StringPiece str);
 
 // Creates a new StringPiece that points to a substring of the original string without trailing
 // whitespace.
-android::StringPiece TrimTrailingWhitespace(const android::StringPiece& str);
+android::StringPiece TrimTrailingWhitespace(android::StringPiece str);
 
 // Creates a new StringPiece that points to a substring of the original string without leading or
 // trailing whitespace.
-android::StringPiece TrimWhitespace(const android::StringPiece& str);
+android::StringPiece TrimWhitespace(android::StringPiece str);
 
 // Tests that the string is a valid Java class name.
-bool IsJavaClassName(const android::StringPiece& str);
+bool IsJavaClassName(android::StringPiece str);
 
 // Tests that the string is a valid Java package name.
-bool IsJavaPackageName(const android::StringPiece& str);
+bool IsJavaPackageName(android::StringPiece str);
 
 // Tests that the string is a valid Android package name. More strict than a Java package name.
 // - First character of each component (separated by '.') must be an ASCII letter.
 // - Subsequent characters of a component can be ASCII alphanumeric or an underscore.
 // - Package must contain at least two components, unless it is 'android'.
 // - The maximum package name length is 223.
-bool IsAndroidPackageName(const android::StringPiece& str);
+bool IsAndroidPackageName(android::StringPiece str);
 
 // Tests that the string is a valid Android split name.
 // - First character of each component (separated by '.') must be an ASCII letter.
 // - Subsequent characters of a component can be ASCII alphanumeric or an underscore.
-bool IsAndroidSplitName(const android::StringPiece& str);
+bool IsAndroidSplitName(android::StringPiece str);
 
 // Tests that the string is a valid Android shared user id.
 // - First character of each component (separated by '.') must be an ASCII letter.
@@ -93,8 +93,7 @@
 // - Must contain at least two components, unless package name is 'android'.
 // - The maximum shared user id length is 223.
 // - Treat empty string as valid, it's the case of no shared user id.
-bool IsAndroidSharedUserId(const android::StringPiece& package_name,
-                           const android::StringPiece& shared_user_id);
+bool IsAndroidSharedUserId(android::StringPiece package_name, android::StringPiece shared_user_id);
 
 // Converts the class name to a fully qualified class name from the given
 // `package`. Ex:
@@ -103,8 +102,8 @@
 // .asdf        --> package.asdf
 // .a.b         --> package.a.b
 // asdf.adsf    --> asdf.adsf
-std::optional<std::string> GetFullyQualifiedClassName(const android::StringPiece& package,
-                                                      const android::StringPiece& class_name);
+std::optional<std::string> GetFullyQualifiedClassName(android::StringPiece package,
+                                                      android::StringPiece class_name);
 
 // Retrieves the formatted name of aapt2.
 const char* GetToolName();
@@ -152,16 +151,16 @@
 // explicitly specifying an index) when there are more than one argument. This is an error
 // because translations may rearrange the order of the arguments in the string, which will
 // break the string interpolation.
-bool VerifyJavaStringFormat(const android::StringPiece& str);
+bool VerifyJavaStringFormat(android::StringPiece str);
 
-bool AppendStyledString(const android::StringPiece& input, bool preserve_spaces,
-                        std::string* out_str, std::string* out_error);
+bool AppendStyledString(android::StringPiece input, bool preserve_spaces, std::string* out_str,
+                        std::string* out_error);
 
 class StringBuilder {
  public:
   StringBuilder() = default;
 
-  StringBuilder& Append(const android::StringPiece& str);
+  StringBuilder& Append(android::StringPiece str);
   const std::string& ToString() const;
   const std::string& Error() const;
   bool IsEmpty() const;
@@ -229,7 +228,7 @@
    private:
     friend class Tokenizer;
 
-    iterator(const android::StringPiece& s, char sep, const android::StringPiece& tok, bool end);
+    iterator(android::StringPiece s, char sep, android::StringPiece tok, bool end);
 
     android::StringPiece str_;
     char separator_;
@@ -237,7 +236,7 @@
     bool end_;
   };
 
-  Tokenizer(const android::StringPiece& str, char sep);
+  Tokenizer(android::StringPiece str, char sep);
 
   iterator begin() const {
     return begin_;
@@ -252,7 +251,7 @@
   const iterator end_;
 };
 
-inline Tokenizer Tokenize(const android::StringPiece& str, char sep) {
+inline Tokenizer Tokenize(android::StringPiece str, char sep) {
   return Tokenizer(str, sep);
 }
 
@@ -263,7 +262,7 @@
 // Extracts ".xml" into outSuffix.
 //
 // Returns true if successful.
-bool ExtractResFilePathParts(const android::StringPiece& path, android::StringPiece* out_prefix,
+bool ExtractResFilePathParts(android::StringPiece path, android::StringPiece* out_prefix,
                              android::StringPiece* out_entry, android::StringPiece* out_suffix);
 
 }  // namespace util
diff --git a/tools/aapt2/util/Util_test.cpp b/tools/aapt2/util/Util_test.cpp
index 4ebcb11..15135690 100644
--- a/tools/aapt2/util/Util_test.cpp
+++ b/tools/aapt2/util/Util_test.cpp
@@ -84,6 +84,14 @@
   ASSERT_THAT(*iter, Eq(StringPiece()));
 }
 
+TEST(UtilTest, TokenizeNone) {
+  auto tokenizer = util::Tokenize(StringPiece("none"), '.');
+  auto iter = tokenizer.begin();
+  ASSERT_THAT(*iter, Eq("none"));
+  ++iter;
+  ASSERT_THAT(iter, Eq(tokenizer.end()));
+}
+
 TEST(UtilTest, IsJavaClassName) {
   EXPECT_TRUE(util::IsJavaClassName("android.test.Class"));
   EXPECT_TRUE(util::IsJavaClassName("android.test.Class$Inner"));