Reland "[Intl] Replace uloc_(to|for)Language w/ Locale API"

This is a reland of 7b744e3a

I cannot reproduce the problem in this reland CL. I think
the origin breakage is just due to test flakiness.
Try to reland it without changes

TBR=jshin@chromium.org

Original change's description:
> [Intl] Replace uloc_(to|for)Language w/ Locale API
>
> Bug: v8:8468
> Change-Id: Id2f8d165e5f29f429821b44def2512fe760c0a51
> Reviewed-on: https://chromium-review.googlesource.com/c/1377989
> Reviewed-by: Jungshik Shin <jshin@chromium.org>
> Reviewed-by: Sathya Gunasekaran <gsathya@chromium.org>
> Commit-Queue: Frank Tang <ftang@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#58260}

Bug: v8:8468
Change-Id: I5f34d061d630d07f5c9da07f9adb1efa040d66d5
Reviewed-on: https://chromium-review.googlesource.com/c/1378658Reviewed-by: Frank Tang <ftang@chromium.org>
Commit-Queue: Frank Tang <ftang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#58297}

src/objects/intl-objects.cc

@@ -407,21 +407,9 @@ icu::Locale Intl::CreateICULocale(const std::string& bcp47_locale) {
 
   // Convert BCP47 into ICU locale format.
   UErrorCode status = U_ZERO_ERROR;
-  char icu_result[ULOC_FULLNAME_CAPACITY];
-  int parsed_length = 0;
 
-  // bcp47_locale_str should be a canonicalized language tag, which
-  // means this shouldn't fail.
-  uloc_forLanguageTag(bcp47_locale.c_str(), icu_result, ULOC_FULLNAME_CAPACITY,
-                      &parsed_length, &status);
+  icu::Locale icu_locale = icu::Locale::forLanguageTag(bcp47_locale, status);
   CHECK(U_SUCCESS(status));
-
-  // bcp47_locale is already checked for its structural validity
-  // so that it should be parsed completely.
-  size_t bcp47_length = bcp47_locale.length();
-  CHECK_EQ(bcp47_length, parsed_length);
-
-  icu::Locale icu_locale(icu_result);
   if (icu_locale.isBogus()) {
     FATAL("Failed to create ICU locale, are ICU data files missing?");
   }

src/objects/js-date-time-format.cc

@@ -284,12 +284,9 @@ MaybeHandle<JSObject> JSDateTimeFormat::ResolvedOptions(
 
   CHECK(!date_time_format->icu_locale().is_null());
   CHECK_NOT_NULL(date_time_format->icu_locale()->raw());
-  UErrorCode status = U_ZERO_ERROR;
-  char language[ULOC_FULLNAME_CAPACITY];
-  uloc_toLanguageTag(date_time_format->icu_locale()->raw()->getName(), language,
-                     ULOC_FULLNAME_CAPACITY, FALSE, &status);
-  CHECK(U_SUCCESS(status));
-  Handle<String> locale = factory->NewStringFromAsciiChecked(language);
+  icu::Locale icu_locale = *(date_time_format->icu_locale()->raw());
+  Handle<String> locale = factory->NewStringFromAsciiChecked(
+      Intl::ToLanguageTag(icu_locale).c_str());
 
   icu::SimpleDateFormat* icu_simple_date_format =
       date_time_format->icu_simple_date_format()->raw();
@@ -313,7 +310,7 @@ MaybeHandle<JSObject> JSDateTimeFormat::ResolvedOptions(
   const icu::TimeZone& tz = calendar->getTimeZone();
   icu::UnicodeString time_zone;
   tz.getID(time_zone);
-  status = U_ZERO_ERROR;
+  UErrorCode status = U_ZERO_ERROR;
   icu::UnicodeString canonical_time_zone;
   icu::TimeZone::getCanonicalID(time_zone, canonical_time_zone, status);
   Handle<Object> timezone_value;

src/objects/js-locale.cc

@@ -312,48 +312,34 @@ MaybeHandle<JSLocale> JSLocale::Initialize(Isolate* isolate,
 }
 
 namespace {
-
-Handle<String> MorphLocale(Isolate* isolate, String language_tag,
-                           int32_t (*morph_func)(const char*, char*, int32_t,
-                                                 UErrorCode*)) {
-  Factory* factory = isolate->factory();
-  char localeBuffer[ULOC_FULLNAME_CAPACITY];
-  char morphBuffer[ULOC_FULLNAME_CAPACITY];
-
+Handle<String> MorphLocale(Isolate* isolate, String locale,
+                           void (*morph_func)(icu::Locale* l,
+                                              UErrorCode* status)) {
   UErrorCode status = U_ZERO_ERROR;
-  // Convert from language id to locale.
-  int32_t parsed_length;
-  int32_t length =
-      uloc_forLanguageTag(language_tag->ToCString().get(), localeBuffer,
-                          ULOC_FULLNAME_CAPACITY, &parsed_length, &status);
-  CHECK(parsed_length == language_tag->length());
-  DCHECK(U_SUCCESS(status));
-  DCHECK_GT(length, 0);
-  DCHECK_NOT_NULL(morph_func);
-  // Add the likely subtags or Minimize the subtags on the locale id
-  length =
-      (*morph_func)(localeBuffer, morphBuffer, ULOC_FULLNAME_CAPACITY, &status);
-  DCHECK(U_SUCCESS(status));
-  DCHECK_GT(length, 0);
-  // Returns a well-formed language tag
-  length = uloc_toLanguageTag(morphBuffer, localeBuffer, ULOC_FULLNAME_CAPACITY,
-                              false, &status);
-  DCHECK(U_SUCCESS(status));
-  DCHECK_GT(length, 0);
-  std::string lang(localeBuffer, length);
-  std::replace(lang.begin(), lang.end(), '_', '-');
-
-  return factory->NewStringFromAsciiChecked(lang.c_str());
+  icu::Locale icu_locale =
+      icu::Locale::forLanguageTag(locale.ToCString().get(), status);
+  CHECK(U_SUCCESS(status));
+  CHECK(!icu_locale.isBogus());
+  (*morph_func)(&icu_locale, &status);
+  CHECK(U_SUCCESS(status));
+  CHECK(!icu_locale.isBogus());
+  return isolate->factory()->NewStringFromAsciiChecked(
+      Intl::ToLanguageTag(icu_locale).c_str());
 }
-
 }  // namespace
 
 Handle<String> JSLocale::Maximize(Isolate* isolate, String locale) {
-  return MorphLocale(isolate, locale, uloc_addLikelySubtags);
+  return MorphLocale(isolate, locale,
+                     [](icu::Locale* icu_locale, UErrorCode* status) {
+                       icu_locale->addLikelySubtags(*status);
+                     });
 }
 
 Handle<String> JSLocale::Minimize(Isolate* isolate, String locale) {
-  return MorphLocale(isolate, locale, uloc_minimizeSubtags);
+  return MorphLocale(isolate, locale,
+                     [](icu::Locale* icu_locale, UErrorCode* status) {
+                       icu_locale->minimizeSubtags(*status);
+                     });
 }
 
 Handle<String> JSLocale::CaseFirstAsString() const {