From 83dcf51c7b1729df3840d77d0b54dfadbc7705eb Mon Sep 17 00:00:00 2001
From: Chris Bracken <chris@bracken.jp>
Date: Sat, 8 May 2021 11:17:41 -0700
Subject: [PATCH] Use string_view inputs for conversion functions
 (flutter/engine#26031)

This offers a small improvement in performance in cases where the input
is a raw char* or wchar_t* string due to not having to perform an
implicit conversion to std::string/std::wstring.

Code cleanup covered by existing tests, which already use raw C strings.
---
 .../src/flutter/shell/platform/windows/string_conversion.cc   | 4 ++--
 engine/src/flutter/shell/platform/windows/string_conversion.h | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/engine/src/flutter/shell/platform/windows/string_conversion.cc b/engine/src/flutter/shell/platform/windows/string_conversion.cc
index 1519337a0ac..d3ab3143ea7 100644
--- a/engine/src/flutter/shell/platform/windows/string_conversion.cc
+++ b/engine/src/flutter/shell/platform/windows/string_conversion.cc
@@ -8,7 +8,7 @@
 
 namespace flutter {
 
-std::string Utf8FromUtf16(const std::wstring& utf16_string) {
+std::string Utf8FromUtf16(const std::wstring_view utf16_string) {
   if (utf16_string.empty()) {
     return std::string();
   }
@@ -30,7 +30,7 @@ std::string Utf8FromUtf16(const std::wstring& utf16_string) {
   return utf8_string;
 }
 
-std::wstring Utf16FromUtf8(const std::string& utf8_string) {
+std::wstring Utf16FromUtf8(const std::string_view utf8_string) {
   if (utf8_string.empty()) {
     return std::wstring();
   }
diff --git a/engine/src/flutter/shell/platform/windows/string_conversion.h b/engine/src/flutter/shell/platform/windows/string_conversion.h
index ce84be2f46f..b79aed47110 100644
--- a/engine/src/flutter/shell/platform/windows/string_conversion.h
+++ b/engine/src/flutter/shell/platform/windows/string_conversion.h
@@ -11,11 +11,11 @@ namespace flutter {
 
 // Converts a string from UTF-16 to UTF-8. Returns an empty string if the
 // input is not valid UTF-16.
-std::string Utf8FromUtf16(const std::wstring& utf16_string);
+std::string Utf8FromUtf16(const std::wstring_view utf16_string);
 
 // Converts a string from UTF-8 to UTF-16. Returns an empty string if the
 // input is not valid UTF-8.
-std::wstring Utf16FromUtf8(const std::string& utf8_string);
+std::wstring Utf16FromUtf8(const std::string_view utf8_string);
 
 }  // namespace flutter