Second part of P0482 - char8_t. Reviewed as https://reviews.llvm.org/D55308

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@348828 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/string_view b/include/string_view
index dd425a2..7d78312 100644
--- a/include/string_view
+++ b/include/string_view
@@ -769,6 +769,9 @@
 }
 
 typedef basic_string_view<char>     string_view;
+#ifndef _LIBCPP_NO_HAS_CHAR8_T
+typedef basic_string_view<char8_t>  u8string_view;
+#endif
 typedef basic_string_view<char16_t> u16string_view;
 typedef basic_string_view<char32_t> u32string_view;
 typedef basic_string_view<wchar_t>  wstring_view;
@@ -802,6 +805,14 @@
         return basic_string_view<wchar_t> (__str, __len);
     }
 
+#ifndef _LIBCPP_NO_HAS_CHAR8_T
+    inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+    basic_string_view<char8_t> operator "" sv(const char8_t *__str, size_t __len) _NOEXCEPT
+    {
+        return basic_string_view<char8_t> (__str, __len);
+    }
+#endif
+
     inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
     basic_string_view<char16_t> operator "" sv(const char16_t *__str, size_t __len) _NOEXCEPT
     {