[inspector] fix typo in fromUTF16LE and cleanup test

Bug: v8:9355
Change-Id: I42a683f9480435499e603083e844a47150ae57c8
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1676244Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Alexei Filippov <alph@chromium.org>
Commit-Queue: Junliang Yan <jyan@ca.ibm.com>
Cr-Commit-Position: refs/heads/master@{#62379}

src/inspector/string-16.cc

@@ -207,7 +207,7 @@ String16 String16::fromUTF16LE(const UChar* stringStart, size_t length) {
   builder.reserveCapacity(length);
   for (size_t i = 0; i < length; i++) {
     const UChar utf16be_char =
-        utf16le_str[i] << 8 | (utf16le_str[i] >> 8 & 0x00FF);
+        stringStart[i] << 8 | (stringStart[i] >> 8 & 0x00FF);
     builder.append(utf16be_char);
   }
   return builder.toString();

src/inspector/string-16.h

@@ -26,7 +26,7 @@ class String16 {
   String16(const String16&) V8_NOEXCEPT = default;
   String16(String16&&) V8_NOEXCEPT = default;
   String16(const UChar* characters, size_t size);
-  String16(const UChar* characters);  // NOLINT(runtime/explicit)
+  V8_EXPORT String16(const UChar* characters);  // NOLINT(runtime/explicit)
   String16(const char* characters);   // NOLINT(runtime/explicit)
   String16(const char* characters, size_t size);
   explicit String16(const std::basic_string<UChar>& impl);

test/cctest/test-inspector.cc

@@ -67,14 +67,14 @@ TEST(WrapInsideWrapOnInterrupt) {
 }
 
 TEST(String16EndianTest) {
-  const char* utf8 =
-      "Hello, \xf0\x9f\x8c\x8e.";  // "Hello, earth." in utf8 encoding
+  const v8_inspector::UChar* expected =
+      reinterpret_cast<const v8_inspector::UChar*>(u"Hello, \U0001F30E.");
   const uint16_t* utf16le = reinterpret_cast<const uint16_t*>(
       "H\0e\0l\0l\0o\0,\0 \0\x3c\xd8\x0e\xdf.\0");  // Same text in UTF16LE
                                                     // encoding
 
   String16 utf16_str = String16::fromUTF16LE(utf16le, 10);
-  String16 utf8_str = String16::fromUTF8(utf8, strlen(utf8));
+  String16 expected_str = expected;
 
-  CHECK_EQ(utf16_str.utf8(), utf8_str.utf8());
+  CHECK_EQ(utf16_str, expected_str);
 }