Obtained from:	https://chromium.googlesource.com/v8/v8.git/+/182d9c05e78b1ddb1cb8242cd3628a7855a0336f

commit 182d9c05e78b1ddb1cb8242cd3628a7855a0336f
Author: Andrey Kosyakov <caseq@chromium.org>
Date:   2023-08-17T13:50:11-07:00

    Define UChar as char16_t
    
    We used to have UChar defined as uint16_t which does not go along
    with STL these days if you try to have an std::basic_string<> of it,
    as there are no standard std::char_traits<> specialization for uint16_t.
    
    This switches UChar to char16_t where practical, introducing a few
    compatibility shims to keep CL size small, as (1) this would likely
    have to be back-ported and (2) crdtp extensively uses uint16_t for
    wide chars.
    
    Bug: b:296390693
    Change-Id: I66a32d8f0050915225b187de56896c26dd76163d
    Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/4789966
    Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
    Commit-Queue: Jaroslav Sevcik <jarin@chromium.org>
    Auto-Submit: Andrey Kosyakov <caseq@chromium.org>
    Cr-Commit-Position: refs/heads/main@{#89559}

diff --git deps/v8/src/inspector/string-16.cc deps/v8/src/inspector/string-16.cc
index a8b786a8166..6df9963e970 100644
--- deps/v8/src/inspector/string-16.cc
+++ deps/v8/src/inspector/string-16.cc
@@ -27,7 +27,7 @@ bool isSpaceOrNewLine(UChar c) {
   return isASCII(c) && c <= ' ' && (c == ' ' || (c <= 0xD && c >= 0x9));
 }
 
-int64_t charactersToInteger(const UChar* characters, size_t length,
+int64_t charactersToInteger(const uint16_t* characters, size_t length,
                             bool* ok = nullptr) {
   std::vector<char> buffer;
   buffer.reserve(length + 1);
@@ -50,6 +50,8 @@ String16::String16(const UChar* characters, size_t siz
 
 String16::String16(const UChar* characters, size_t size)
     : m_impl(characters, size) {}
+String16::String16(const uint16_t* characters, size_t size)
+    : m_impl(reinterpret_cast<const UChar*>(characters), size) {}
 
 String16::String16(const UChar* characters) : m_impl(characters) {}
 
@@ -231,6 +233,10 @@ String16 String16::fromUTF16LE(const UChar* stringStar
   // No need to do anything on little endian machines.
   return String16(stringStart, length);
 #endif  // V8_TARGET_BIG_ENDIAN
+}
+
+String16 String16::fromUTF16LE(const uint16_t* stringStart, size_t length) {
+  return fromUTF16LE(reinterpret_cast<const UChar*>(stringStart), length);
 }
 
 std::string String16::utf8() const {
diff --git deps/v8/src/inspector/string-16.h deps/v8/src/inspector/string-16.h
index 1678ffb2e1e..d9f6c466ab1 100644
--- deps/v8/src/inspector/string-16.h
+++ deps/v8/src/inspector/string-16.h
@@ -6,6 +6,7 @@
 #define V8_INSPECTOR_STRING_16_H_
 
 #include <stdint.h>
+#include <uchar.h>
 
 #include <cctype>
 #include <climits>
@@ -17,7 +18,7 @@ namespace v8_inspector {
 
 namespace v8_inspector {
 
-using UChar = uint16_t;
+using UChar = char16_t;
 
 class String16 {
  public:
@@ -27,6 +28,7 @@ class String16 {
   String16(const String16&) V8_NOEXCEPT = default;
   String16(String16&&) V8_NOEXCEPT = default;
   String16(const UChar* characters, size_t size);
+  String16(const uint16_t* characters, size_t size);
   V8_EXPORT String16(const UChar* characters);
   V8_EXPORT String16(const char* characters);
   String16(const char* characters, size_t size);
@@ -47,7 +49,9 @@ class String16 {
   uint64_t toUInt64(bool* ok = nullptr) const;
   int toInteger(bool* ok = nullptr) const;
   String16 stripWhiteSpace() const;
-  const UChar* characters16() const { return m_impl.c_str(); }
+  const uint16_t* characters16() const {
+    return reinterpret_cast<const uint16_t*>(m_impl.c_str());
+  }
   size_t length() const { return m_impl.length(); }
   bool isEmpty() const { return !m_impl.length(); }
   UChar operator[](size_t index) const { return m_impl[index]; }
@@ -76,6 +80,8 @@ class String16 {
   // Instantiates a String16 in native endianness from UTF16 LE.
   // On Big endian architectures, byte order needs to be flipped.
   V8_EXPORT static String16 fromUTF16LE(const UChar* stringStart,
+                                        size_t length);
+  V8_EXPORT static String16 fromUTF16LE(const uint16_t* stringStart,
                                         size_t length);
 
   std::size_t hash() const {
diff --git deps/v8/src/inspector/v8-string-conversions.cc deps/v8/src/inspector/v8-string-conversions.cc
index 0c75e66b972..8cf19be816c 100644
--- deps/v8/src/inspector/v8-string-conversions.cc
+++ deps/v8/src/inspector/v8-string-conversions.cc
@@ -12,7 +12,7 @@ namespace {
 
 namespace v8_inspector {
 namespace {
-using UChar = uint16_t;
+using UChar = char16_t;
 using UChar32 = uint32_t;
 
 bool isASCII(UChar c) { return !(c & ~0x7F); }
@@ -386,7 +386,7 @@ std::basic_string<UChar> UTF8ToUTF16(const char* strin
 
 std::basic_string<UChar> UTF8ToUTF16(const char* stringStart, size_t length) {
   if (!stringStart || !length) return std::basic_string<UChar>();
-  std::vector<uint16_t> buffer(length);
+  std::vector<UChar> buffer(length);
   UChar* bufferStart = buffer.data();
 
   UChar* bufferCurrent = bufferStart;
@@ -395,7 +395,7 @@ std::basic_string<UChar> UTF8ToUTF16(const char* strin
                          reinterpret_cast<const char*>(stringStart + length),
                          &bufferCurrent, bufferCurrent + buffer.size(), nullptr,
                          true) != conversionOK)
-    return std::basic_string<uint16_t>();
+    return std::basic_string<UChar>();
   size_t utf16Length = bufferCurrent - bufferStart;
   return std::basic_string<UChar>(bufferStart, bufferStart + utf16Length);
 }
diff --git deps/v8/src/inspector/v8-string-conversions.h deps/v8/src/inspector/v8-string-conversions.h
index eb33c6816a5..1126255dac2 100644
--- deps/v8/src/inspector/v8-string-conversions.h
+++ deps/v8/src/inspector/v8-string-conversions.h
@@ -5,14 +5,16 @@
 #ifndef V8_INSPECTOR_V8_STRING_CONVERSIONS_H_
 #define V8_INSPECTOR_V8_STRING_CONVERSIONS_H_
 
+#include <uchar.h>
+
 #include <cstdint>
 #include <string>
 
 // Conversion routines between UT8 and UTF16, used by string-16.{h,cc}. You may
 // want to use string-16.h directly rather than these.
 namespace v8_inspector {
-std::basic_string<uint16_t> UTF8ToUTF16(const char* stringStart, size_t length);
-std::string UTF16ToUTF8(const uint16_t* stringStart, size_t length);
+std::basic_string<char16_t> UTF8ToUTF16(const char* stringStart, size_t length);
+std::string UTF16ToUTF8(const char16_t* stringStart, size_t length);
 }  // namespace v8_inspector
 
 #endif  // V8_INSPECTOR_V8_STRING_CONVERSIONS_H_
diff --git deps/v8/third_party/inspector_protocol/crdtp/test_platform_v8.cc deps/v8/third_party/inspector_protocol/crdtp/test_platform_v8.cc
index c9d89eaa42f..1a46d781b89 100644
--- deps/v8/third_party/inspector_protocol/crdtp/test_platform_v8.cc
+++ deps/v8/third_party/inspector_protocol/crdtp/test_platform_v8.cc
@@ -11,13 +11,16 @@ std::string UTF16ToUTF8(span<uint16_t> in) {
 namespace v8_crdtp {
 
 std::string UTF16ToUTF8(span<uint16_t> in) {
-  return v8_inspector::UTF16ToUTF8(in.data(), in.size());
+  return v8_inspector::UTF16ToUTF8(reinterpret_cast<const char16_t*>(in.data()),
+                                   in.size());
 }
 
 std::vector<uint16_t> UTF8ToUTF16(span<uint8_t> in) {
-  std::basic_string<uint16_t> utf16 = v8_inspector::UTF8ToUTF16(
+  std::basic_string<char16_t> utf16 = v8_inspector::UTF8ToUTF16(
       reinterpret_cast<const char*>(in.data()), in.size());
-  return std::vector<uint16_t>(utf16.begin(), utf16.end());
+  return std::vector<uint16_t>(
+      reinterpret_cast<const uint16_t*>(utf16.data()),
+      reinterpret_cast<const uint16_t*>(utf16.data()) + utf16.size());
 }
 
 }  // namespace v8_crdtp
