Make UTF16ToASCII and UTF16TOUTF8 take a StringPiece

base/strings/utf_string_conversions.h

Index: base/strings/utf_string_conversions.h
diff --git a/base/strings/utf_string_conversions.h b/base/strings/utf_string_conversions.h
index 06a3bc64767791909dd6a3d0b454bda972812f73..9b15730df3863b7f8809c9d31802feb813157387 100644
--- a/base/strings/utf_string_conversions.h
+++ b/base/strings/utf_string_conversions.h
@@ -24,7 +24,7 @@ BASE_EXPORT bool WideToUTF8(const wchar_t* src, size_t src_len,
 BASE_EXPORT std::string WideToUTF8(const std::wstring& wide);
 BASE_EXPORT bool UTF8ToWide(const char* src, size_t src_len,
                             std::wstring* output);
-BASE_EXPORT std::wstring UTF8ToWide(const StringPiece& utf8);
+BASE_EXPORT std::wstring UTF8ToWide(StringPiece utf8);
 
 BASE_EXPORT bool WideToUTF16(const wchar_t* src, size_t src_len,
                              string16* output);
@@ -34,18 +34,18 @@ BASE_EXPORT bool UTF16ToWide(const char16* src, size_t src_len,
 BASE_EXPORT std::wstring UTF16ToWide(const string16& utf16);
 
 BASE_EXPORT bool UTF8ToUTF16(const char* src, size_t src_len, string16* output);
-BASE_EXPORT string16 UTF8ToUTF16(const StringPiece& utf8);
+BASE_EXPORT string16 UTF8ToUTF16(StringPiece utf8);
 BASE_EXPORT bool UTF16ToUTF8(const char16* src, size_t src_len,
                              std::string* output);
-BASE_EXPORT std::string UTF16ToUTF8(const string16& utf16);
+BASE_EXPORT std::string UTF16ToUTF8(StringPiece16 utf16);
 
 // This converts an ASCII string, typically a hardcoded constant, to a UTF16
 // string.
-BASE_EXPORT string16 ASCIIToUTF16(const StringPiece& ascii);
+BASE_EXPORT string16 ASCIIToUTF16(StringPiece ascii);
 
 // Converts to 7-bit ASCII by truncating. The result must be known to be ASCII
 // beforehand.
-BASE_EXPORT std::string UTF16ToASCII(const string16& utf16);
+BASE_EXPORT std::string UTF16ToASCII(StringPiece16 utf16);
 
 }  // namespace base