[Intl] Fix the dangling pointers in IsStructurallyValidLanguageTag

This is a part of larger cl https://chromium-review.googlesource.com/c/v8/v8/+/1144524
"Port canonicalizeLanguageTag and isStructuallyValidLanguageTag from JS to C++."

This is being separated out because:
1) this will unblock ftang's work
2) there is an increased memory usage issue report I'd like to understand before
   connecting IsStructurallyValidLanguageTag for widespread usage

The memory concern will be dealt with in a follow-up cl.

Also in this cl:
Fix to ignore the first tag when checking for duplicate subtags.

Cq-Include-Trybots: luci.v8.try:v8_linux_noi18n_rel_ng
Change-Id: I76f4f6861490d8f9ccb36d6a0f7a7d5fa32ff995
Reviewed-on: https://chromium-review.googlesource.com/1147561Reviewed-by: Sathya Gunasekaran <gsathya@chromium.org>
Reviewed-by: Jungshik Shin <jshin@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Commit-Queue: Brian Stell <bstell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#54653}

src/objects/intl-objects.cc

@@ -1495,8 +1495,10 @@ bool IsStructurallyValidLanguageTag(Isolate* isolate,
       GetLanguageTagRegexMatcher(isolate);
 
   // Check if it's well-formed, including grandfathered tags.
-  language_tag_regexp_matcher->reset(
-      icu::UnicodeString(locale.c_str(), -1, US_INV));
+  icu::UnicodeString locale_uni(locale.c_str(), -1, US_INV);
+  // Note: icu::RegexMatcher::reset does not make a copy of the input string
+  // so cannot use a temp value; ie: cannot create it as a call parameter.
+  language_tag_regexp_matcher->reset(locale_uni);
   UErrorCode status = U_ZERO_ERROR;
   bool is_valid_lang_tag = language_tag_regexp_matcher->matches(status);
   if (!is_valid_lang_tag || V8_UNLIKELY(U_FAILURE(status))) {
@@ -1537,33 +1539,33 @@ bool IsStructurallyValidLanguageTag(Isolate* isolate,
 
   std::vector<std::string> variants;
   std::vector<std::string> extensions;
-  for (const auto& value : parts) {
-    language_variant_regexp_matcher->reset(
-        icu::UnicodeString::fromUTF8(value.c_str()));
+  for (auto it = parts.begin() + 1; it != parts.end(); it++) {
+    icu::UnicodeString part(it->data(), -1, US_INV);
+    // Note: icu::RegexMatcher::reset does not make a copy of the input string
+    // so cannot use a temp value; ie: cannot create it as a call parameter.
+    language_variant_regexp_matcher->reset(part);
     bool is_language_variant = language_variant_regexp_matcher->matches(status);
     if (V8_UNLIKELY(U_FAILURE(status))) {
       return false;
     }
     if (is_language_variant && extensions.size() == 0) {
-      if (std::find(variants.begin(), variants.end(), value) ==
-          variants.end()) {
-        variants.push_back(value);
+      if (std::find(variants.begin(), variants.end(), *it) == variants.end()) {
+        variants.push_back(*it);
       } else {
         return false;
       }
     }
 
-    language_singleton_regexp_matcher->reset(
-        icu::UnicodeString(value.c_str(), -1, US_INV));
+    language_singleton_regexp_matcher->reset(part);
     bool is_language_singleton =
         language_singleton_regexp_matcher->matches(status);
     if (V8_UNLIKELY(U_FAILURE(status))) {
       return false;
     }
     if (is_language_singleton) {
-      if (std::find(extensions.begin(), extensions.end(), value) ==
+      if (std::find(extensions.begin(), extensions.end(), *it) ==
           extensions.end()) {
-        extensions.push_back(value);
+        extensions.push_back(*it);
       } else {
         return false;
       }
@@ -1582,8 +1584,8 @@ bool IsTwoLetterLanguage(const std::string& locale) {
 }
 
 bool IsDeprecatedLanguage(const std::string& locale) {
-  //  Not one of the deprecated language tags:
-  return locale != "in" && locale != "iw" && locale != "ji" && locale != "jw";
+  //  Check if locale is one of the deprecated language tags:
+  return locale == "in" || locale == "iw" || locale == "ji" || locale == "jw";
 }
 
 }  // anonymous namespace
@@ -1613,8 +1615,10 @@ MaybeHandle<String> Intl::CanonicalizeLanguageTag(Isolate* isolate,
   }
 
   if (!IsStructurallyValidLanguageTag(isolate, locale)) {
-    THROW_NEW_ERROR(isolate, NewTypeError(MessageTemplate::kInvalidLanguageTag),
-                    String);
+    THROW_NEW_ERROR(
+        isolate,
+        NewRangeError(MessageTemplate::kInvalidLanguageTag, locale_str),
+        String);
   }
 
   // // ECMA 402 6.2.3
@@ -1632,7 +1636,9 @@ MaybeHandle<String> Intl::CanonicalizeLanguageTag(Isolate* isolate,
     // TODO(jshin): This should not happen because the structural validity
     // is already checked. If that's the case, remove this.
     THROW_NEW_ERROR(
-        isolate, NewRangeError(MessageTemplate::kInvalidLanguageTag), String);
+        isolate,
+        NewRangeError(MessageTemplate::kInvalidLanguageTag, locale_str),
+        String);
   }
 
   // Force strict BCP47 rules.
@@ -1642,7 +1648,9 @@ MaybeHandle<String> Intl::CanonicalizeLanguageTag(Isolate* isolate,
 
   if (U_FAILURE(error)) {
     THROW_NEW_ERROR(
-        isolate, NewRangeError(MessageTemplate::kInvalidLanguageTag), String);
+        isolate,
+        NewRangeError(MessageTemplate::kInvalidLanguageTag, locale_str),
+        String);
   }
 
   return isolate->factory()