Reapply "Changes according to review comments"

base/android/locale_utils.cc

+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "base/android/locale_utils.h"
+
+#include "base/android/jni_android.h"
+#include "base/android/jni_string.h"
+#include "base/android/scoped_java_ref.h"
+#include "base/logging.h"
+#include "base/string_util.h"
+#include "jni/locale_utils_jni.h"
+#include "unicode/uloc.h"
+
+namespace base {
+namespace android {
+
+std::string GetDefaultLocale() {
+  JNIEnv* env = AttachCurrentThread();
+  ScopedJavaLocalRef<jstring> locale = Java_LocaleUtils_getDefaultLocale(env);
+  return ConvertJavaStringToUTF8(locale);
+}
+
+namespace {
+
+// Common prototype of ICU uloc_getXXX() functions.
+typedef int32_t (*UlocGetComponentFunc)(const char*, char*, int32_t,
+                                        UErrorCode*);
+
+std::string GetLocaleComponent(const std::string& locale,
+                               UlocGetComponentFunc uloc_func,
+                               int32_t max_capacity) {
+  std::string result;
+  UErrorCode error = U_ZERO_ERROR;
+  int32_t actual_length = uloc_func(locale.c_str(),
+                                    WriteInto(&result, max_capacity),
+                                    max_capacity,
+                                    &error);
+  DCHECK(U_SUCCESS(error));
+  DCHECK(actual_length < max_capacity);
+  result.resize(actual_length);
+  return result;
+}
+
+ScopedJavaLocalRef<jobject> NewJavaLocale(
+    JNIEnv* env,
+    ScopedJavaLocalRef<jclass> locale_class,
+    jmethodID constructor_id,
+    const std::string& locale) {
+  // TODO(wangxianzhu): Use new Locale API once Android supports scripts.
+  std::string language = GetLocaleComponent(
+      locale, uloc_getLanguage, ULOC_LANG_CAPACITY);
+  std::string country = GetLocaleComponent(
+      locale, uloc_getCountry, ULOC_COUNTRY_CAPACITY);
+  std::string variant = GetLocaleComponent(
+      locale, uloc_getVariant, ULOC_FULLNAME_CAPACITY);
+  return ScopedJavaLocalRef<jobject>(
+      env, env->NewObject(
+          locale_class.obj(), constructor_id,
+          ConvertUTF8ToJavaString(env, language).obj(),
+          ConvertUTF8ToJavaString(env, country).obj(),
+          ConvertUTF8ToJavaString(env, variant).obj()));
+}
+
+}  // namespace
+
+string16 GetDisplayNameForLocale(const std::string& locale,
+                                 const std::string& display_locale) {
+  JNIEnv* env = AttachCurrentThread();
+
+  ScopedJavaLocalRef<jclass> locale_class = GetClass(env, "java/util/Locale");
+  jmethodID constructor_id = GetMethodID(
+      env, locale_class, "<init>",
+      "(Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;)V");
+  ScopedJavaLocalRef<jobject> java_locale = NewJavaLocale(
+      env, locale_class, constructor_id, locale);
+  ScopedJavaLocalRef<jobject> java_display_locale = NewJavaLocale(
+      env, locale_class, constructor_id, display_locale);
+
+  jmethodID method_id = GetMethodID(env, locale_class, "getDisplayName",
+                                    "(Ljava/util/Locale;)Ljava/lang/String;");
+  ScopedJavaLocalRef<jstring> java_result(
+      env,
+      static_cast<jstring>(env->CallObjectMethod(java_locale.obj(), method_id,
+                                                 java_display_locale.obj())));
+  return ConvertJavaStringToUTF16(java_result);
+}
+
+bool RegisterLocaleUtils(JNIEnv* env) {
+  return RegisterNativesImpl(env);
+}
+
+}  // namespace android
+}  // namespace base