Use LocaleList in Android/Webview locale representation

base/android/java/src/org/chromium/base/LocaleUtils.java

Index: base/android/java/src/org/chromium/base/LocaleUtils.java
diff --git a/base/android/java/src/org/chromium/base/LocaleUtils.java b/base/android/java/src/org/chromium/base/LocaleUtils.java
index 31e5c4294beafcc99f3d48eed1675e93cd7dd720..04cbd8f9aae8fbadadee0e6767e29fb7128d371e 100644
--- a/base/android/java/src/org/chromium/base/LocaleUtils.java
+++ b/base/android/java/src/org/chromium/base/LocaleUtils.java
@@ -6,9 +6,12 @@ package org.chromium.base;
 
 import android.annotation.TargetApi;
 import android.os.Build;
+import android.os.LocaleList;
+import android.text.TextUtils;
 
 import org.chromium.base.annotations.CalledByNative;
 
+import java.util.ArrayList;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.Locale;
@@ -60,7 +63,8 @@ public class LocaleUtils {
      *         codes used by Chromium.
      */
     @TargetApi(Build.VERSION_CODES.LOLLIPOP)
-    private static Locale getUpdatedLocaleForChromium(Locale locale) {
+    @VisibleForTesting
+    public static Locale getUpdatedLocaleForChromium(Locale locale) {
         String languageForChrome = LANGUAGE_MAP_FOR_CHROMIUM.get(locale.getLanguage());
         if (languageForChrome == null) {
             return locale;
@@ -84,7 +88,8 @@ public class LocaleUtils {
      *         codes used by Chromium.
      */
     @TargetApi(Build.VERSION_CODES.LOLLIPOP)
-    private static Locale getUpdatedLocaleForAndroid(Locale locale) {
+    @VisibleForTesting
+    public static Locale getUpdatedLocaleForAndroid(Locale locale) {
         String languageForAndroid = LANGUAGE_MAP_FOR_ANDROID.get(locale.getLanguage());
         if (languageForAndroid == null) {
             return locale;
@@ -93,7 +98,7 @@ public class LocaleUtils {
     }
 
     /**
-     * This function creates Locale object from xx-XX style string where xx is language code
+     * This function creates a Locale object from xx-XX style string where xx is language code
      * and XX is a country code. This works for API level lower than 21.
      * @return the locale that best represents the language tag.
      */
@@ -117,7 +122,7 @@ public class LocaleUtils {
     }
 
     /**
-     * This function creates Locale object from xx-XX style string where xx is language code
+     * This function creates a Locale object from xx-XX style string where xx is language code
      * and XX is a country code.
      * @return the locale that best represents the language tag.
      */
@@ -132,10 +137,16 @@ public class LocaleUtils {
     /**
      * Converts Locale object to the BCP 47 compliant string format.
      * This works for API level lower than 24.
+     *
+     * Note that for Android M or before, we cannot use Locale.getLanguage() and
+     * Locale.toLanguageTag() for this purpose. Since Locale.getLanguage() returns deprecated
+     * language code even if the Locale object is constructed with updated language code. As for
+     * Locale.toLanguageTag(), it does a special conversion from deprecated language code to updated
+     * one, but it is only usable for Android N or after.
      * @return a well-formed IETF BCP 47 language tag with language and country code that
      *         represents this locale.
      */
-    public static String toLanguageTagCompat(Locale locale) {
+    public static String toLanguageTag(Locale locale) {
         String language = getUpdatedLanguageForChromium(locale.getLanguage());
         String country = locale.getCountry();
         if (language.equals("no") && country.equals("NO") && locale.getVariant().equals("NY")) {
@@ -145,33 +156,32 @@ public class LocaleUtils {
     }
 
     /**
-     * Converts Locale object to the BCP 47 compliant string format.
+     * Converts LocaleList object to the comma separated BCP 47 compliant string format.
      *
-     * Note that for Android M or before, we cannot use Locale.getLanguage() and
-     * Locale.toLanguageTag() for this purpose. Since Locale.getLanguage() returns deprecated
-     * language code even if the Locale object is constructed with updated language code. As for
-     * Locale.toLanguageTag(), it does a special conversion from deprecated language code to updated
-     * one, but it is only usable for Android N or after.
      * @return a well-formed IETF BCP 47 language tag with language and country code that
-     *         represents this locale.
+     *         represents this locale list.
      */
-    public static String toLanguageTag(Locale locale) {
-        // TODO(yirui): use '>= N' once SDK is updated to include the version code
-        if (Build.VERSION.SDK_INT > Build.VERSION_CODES.M) {
-            locale = getUpdatedLocaleForChromium(locale);
-            return locale.toLanguageTag();
+    @TargetApi(Build.VERSION_CODES.N)
+    public static String toLanguageTags(LocaleList localeList) {
+        ArrayList<String> newLocaleList = new ArrayList<>();
+        for (int i = 0; i < localeList.size(); i++) {
+            Locale locale = getUpdatedLocaleForChromium(localeList.get(i));
+            newLocaleList.add(toLanguageTag(locale));
         }
-        return toLanguageTagCompat(locale);
+        return TextUtils.join(",", newLocaleList);
     }
 
     /**
-     * @return a well-formed IETF BCP 47 language tag with language and country code that
-     *         represents a default locale.
+     * @return a comma separated language tags string that represents a default locale or locales.
+     *         Each language tag is well-formed IETF BCP 47 language tag with language and country
+     *         code.
      */
     @CalledByNative
     public static String getDefaultLocaleString() {
-        Locale locale = Locale.getDefault();
-        return toLanguageTag(locale);
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
+            return toLanguageTags(LocaleList.getAdjustedDefault());
+        }
+        return toLanguageTag(Locale.getDefault());
     }
 
     /**