chrome/browser/language/android/java/src/org/chromium/chrome/browser/language/settings/LanguagesManager.java - chromium/src - Git at Google

 // Copyright 2017 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.

 package org.chromium.chrome.browser.language.settings;

 import android.text.TextUtils;

 import androidx.annotation.IntDef;
 import androidx.core.util.Predicate;

 import org.chromium.base.LocaleUtils;
 import org.chromium.base.metrics.RecordHistogram;
 import org.chromium.chrome.browser.language.AppLocaleUtils;
 import org.chromium.chrome.browser.translate.TranslateBridge;

 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.HashSet;
 import java.util.LinkedHashMap;
 import java.util.LinkedHashSet;
 import java.util.List;
 import java.util.Map;
 import java.util.TreeSet;

 /**
  * Manages languages details for languages settings.
  *
  *The LanguagesManager is responsible for fetching languages details from native.
  */
 public class LanguagesManager {
     /**
      * An observer interface that allows other classes to know when the accept language list is
      * updated in native side.
      */
     interface AcceptLanguageObserver {
         /**
          * Called when the accept languages for the current user are updated.
          */
         void onDataUpdated();
     }

     // Constants used to log UMA enum histogram, must stay in sync with
     // LanguageSettingsActionType. Further actions can only be appended, existing
     // entries must not be overwritten.
     @IntDef({LanguageSettingsActionType.LANGUAGE_ADDED, LanguageSettingsActionType.LANGUAGE_REMOVED,
             LanguageSettingsActionType.DISABLE_TRANSLATE_GLOBALLY,
             LanguageSettingsActionType.ENABLE_TRANSLATE_GLOBALLY,
             LanguageSettingsActionType.DISABLE_TRANSLATE_FOR_SINGLE_LANGUAGE,
             LanguageSettingsActionType.ENABLE_TRANSLATE_FOR_SINGLE_LANGUAGE,
             LanguageSettingsActionType.LANGUAGE_LIST_REORDERED,
             LanguageSettingsActionType.CHANGE_CHROME_LANGUAGE,
             LanguageSettingsActionType.CHANGE_TARGET_LANGUAGE,
             LanguageSettingsActionType.REMOVE_FROM_NEVER_TRANSLATE,
             LanguageSettingsActionType.ADD_TO_NEVER_TRANSLATE,
             LanguageSettingsActionType.REMOVE_FROM_ALWAYS_TRANSLATE,
             LanguageSettingsActionType.ADD_TO_ALWAYS_TRANSLATE,
             LanguageSettingsActionType.REMOVE_SITE_FROM_NEVER_TRANSLATE})
     @Retention(RetentionPolicy.SOURCE)
     @interface LanguageSettingsActionType {
         // int CLICK_ON_ADD_LANGUAGE = 1; // Removed M89
         int LANGUAGE_ADDED = 2;
         int LANGUAGE_REMOVED = 3;
         int DISABLE_TRANSLATE_GLOBALLY = 4;
         int ENABLE_TRANSLATE_GLOBALLY = 5;
         int DISABLE_TRANSLATE_FOR_SINGLE_LANGUAGE = 6;
         int ENABLE_TRANSLATE_FOR_SINGLE_LANGUAGE = 7;
         int LANGUAGE_LIST_REORDERED = 8;
         int CHANGE_CHROME_LANGUAGE = 9;
         int CHANGE_TARGET_LANGUAGE = 10;
         int REMOVE_FROM_NEVER_TRANSLATE = 11;
         int ADD_TO_NEVER_TRANSLATE = 12;
         int REMOVE_FROM_ALWAYS_TRANSLATE = 13;
         int ADD_TO_ALWAYS_TRANSLATE = 14;
         int REMOVE_SITE_FROM_NEVER_TRANSLATE = 15;
         int NUM_ENTRIES = 16;
     }

     // Constants used to log UMA enum histogram, must stay in sync with
     // LanguageSettingsPageType. Further actions can only be appended, existing
     // entries must not be overwritten.
     @IntDef({LanguageSettingsPageType.PAGE_MAIN,
             LanguageSettingsPageType.CONTENT_LANGUAGE_ADD_LANGUAGE,
             LanguageSettingsPageType.CHANGE_CHROME_LANGUAGE,
             LanguageSettingsPageType.ADVANCED_LANGUAGE_SETTINGS,
             LanguageSettingsPageType.CHANGE_TARGET_LANGUAGE,
             LanguageSettingsPageType.LANGUAGE_OVERFLOW_MENU_OPENED,
             LanguageSettingsPageType.VIEW_NEVER_TRANSLATE_LANGUAGES,
             LanguageSettingsPageType.NEVER_TRANSLATE_ADD_LANGUAGE,
             LanguageSettingsPageType.VIEW_ALWAYS_TRANSLATE_LANGUAGES,
             LanguageSettingsPageType.ALWAYS_TRANSLATE_ADD_LANGUAGE,
             LanguageSettingsPageType.VIEW_NEVER_TRANSLATE_SITES})
     @Retention(RetentionPolicy.SOURCE)
     @interface LanguageSettingsPageType {
         int PAGE_MAIN = 0;
         int CONTENT_LANGUAGE_ADD_LANGUAGE = 1;
         // int LANGUAGE_DETAILS = 2; // iOS only
         int CHANGE_CHROME_LANGUAGE = 3;
         int ADVANCED_LANGUAGE_SETTINGS = 4;
         int CHANGE_TARGET_LANGUAGE = 5;
         int LANGUAGE_OVERFLOW_MENU_OPENED = 6;
         int VIEW_NEVER_TRANSLATE_LANGUAGES = 7;
         int NEVER_TRANSLATE_ADD_LANGUAGE = 8;
         int VIEW_ALWAYS_TRANSLATE_LANGUAGES = 9;
         int ALWAYS_TRANSLATE_ADD_LANGUAGE = 10;
         int VIEW_NEVER_TRANSLATE_SITES = 11;
         int NUM_ENTRIES = 12;
     }

     // Int keys to determine the list of potential languages for different language preferences.
     @IntDef({LanguageListType.ACCEPT_LANGUAGES, LanguageListType.UI_LANGUAGES,
             LanguageListType.TARGET_LANGUAGES, LanguageListType.NEVER_LANGUAGES,
             LanguageListType.ALWAYS_LANGUAGES})
     @Retention(RetentionPolicy.SOURCE)
     @interface LanguageListType {
         int ACCEPT_LANGUAGES = 0; // Default
         int UI_LANGUAGES = 1;
         int TARGET_LANGUAGES = 2;
         int NEVER_LANGUAGES = 3;
         int ALWAYS_LANGUAGES = 4;
     }

     private static LanguagesManager sManager;

     private final Map<String, LanguageItem> mLanguagesMap;

     private AcceptLanguageObserver mObserver;

     private LanguagesManager() {
         // Get all language data from native.
         mLanguagesMap = new LinkedHashMap<>();
         for (LanguageItem item : TranslateBridge.getChromeLanguageList()) {
             mLanguagesMap.put(item.getCode(), item);
         }
     }

     private void notifyAcceptLanguageObserver() {
         if (mObserver != null) mObserver.onDataUpdated();
     }

     /**
      * Sets the observer tracking the user accept languages changes.
      */
     public void setAcceptLanguageObserver(AcceptLanguageObserver observer) {
         mObserver = observer;
     }

     /**
      * @return A list of LanguageItems for the current user's accept languages.
      */
     public List<LanguageItem> getUserAcceptLanguageItems() {
         // Always read the latest user accept language code list from native.
         List<String> codes = TranslateBridge.getUserLanguageCodes();

         List<LanguageItem> results = new ArrayList<>();
         // Keep the same order as accept language codes list.
         for (String code : codes) {
             // Check language code and only languages supported on Android are added in.
             if (mLanguagesMap.containsKey(code)) results.add(mLanguagesMap.get(code));
         }
         return results;
     }

     /**
      * Get the list of potential languages to show in the {@link AddLanguageFragment} based on which
      * list or preference a language will be added to. By default the potential languages for the
      * Accept-Language list is returned.
      * @param LanguageListType key to select which languages to get.
      * @return A list of LanguageItems to choose from for the given preference.
      */
     public List<LanguageItem> getPotentialLanguages(@LanguageListType int potentialLanguages) {
         switch (potentialLanguages) {
             case LanguageListType.ALWAYS_LANGUAGES:
                 return getPotentialTranslateLanguages(
                         TranslateBridge.getAlwaysTranslateLanguages());
             case LanguageListType.NEVER_LANGUAGES:
                 return getPotentialTranslateLanguages(TranslateBridge.getNeverTranslateLanguages());
             case LanguageListType.TARGET_LANGUAGES:
                 return getPotentialTranslateLanguages(
                         Arrays.asList(TranslateBridge.getTargetLanguageForChromium()));
             case LanguageListType.UI_LANGUAGES:
                 return getPotentialUiLanguages();
             case LanguageListType.ACCEPT_LANGUAGES:
                 return getPotentialAcceptLanguages();
             default:
                 assert false : "No valid LanguageListType";
                 return null;
         }
     }

     /**
      * Get a list of LanguageItems that can be used as a Translate language but excluding
      * |codesToSkip|. The current Accept-Languages are added to the front of the list.
      * @param codesToSkip Collection of String language codes to exclude from the list.
      * @return List of LanguageItems.
      */
     private List<LanguageItem> getPotentialTranslateLanguages(Collection<String> codesToSkip) {
         HashSet<String> codesToSkipSet = new HashSet<String>(codesToSkip);
         LinkedHashSet<LanguageItem> results = new LinkedHashSet<>();
         // Filter for translatable languages not in |codesToSkipSet|.
         Predicate<LanguageItem> filter = (item) -> {
             return item.isSupportedBaseLanguage() && !codesToSkipSet.contains(item.getCode());
         };
         addItemsToResult(results, getUserAcceptLanguageItems(), filter);
         addItemsToResult(results, mLanguagesMap.values(), filter);
         return new ArrayList<>(results);
     }

     /**
      * Get a list of potential LanguageItems Chrome UI languages excluding the current UI language.
      * The current Accept-Languages are added to the front of the the list.
      * @return List of LanguageItems.
      */
     public List<LanguageItem> getPotentialUiLanguages() {
         LinkedHashSet<LanguageItem> results = new LinkedHashSet<>();
         LanguageItem currentUiLanguage = getLanguageItem(AppLocaleUtils.getAppLanguagePref());

         // Add the system default language if an override language is set.
         if (!currentUiLanguage.isSystemDefault()) {
             results.add(LanguageItem.makeSystemDefaultLanguageItem());
         }

         // Filter for UI languages that are not the current UI language.
         Predicate<LanguageItem> filter = (item) -> {
             return item.isUISupported() && !item.equals(currentUiLanguage);
         };
         addItemsToResult(results, getUserAcceptLanguageItems(), filter);
         addItemsToResult(results, mLanguagesMap.values(), filter);
         return new ArrayList<>(results);
     }

     /**
      * Get a list of potential Accept-Languages excluding the current Accept-Languages.
      * @return A list of LanguageItems, excluding the current user's accept languages.
      */
     private List<LanguageItem> getPotentialAcceptLanguages() {
         // Always read the latest user accept language code list from native.
         HashSet<String> codesToSkip = new HashSet(TranslateBridge.getUserLanguageCodes());
         LinkedHashSet<LanguageItem> results = new LinkedHashSet<>();
         addItemsToResult(
                 results, mLanguagesMap.values(), (item) -> !codesToSkip.contains(item.getCode()));
         return new ArrayList<>(results);
     }

     /**
      * Add LanguageItems in |items| to |results| keeping their order and excluding items that match
      * |filter|.
      * @param results LinkedHashSet of LanguageItems to add items to.
      * @param items Collection of LanguageItems to potentially add to results.
      * @param filter Predicate to return true for items that should be added to results.
      */
     private void addItemsToResult(LinkedHashSet<LanguageItem> results,
             Collection<LanguageItem> items, Predicate<LanguageItem> filter) {
         for (LanguageItem item : items) {
             if (filter.test(item)) {
                 results.add(item);
             }
         }
     }

     /**
      * Get a list of LanguageItems that the user has set to always translate. The list is sorted
      * alphabetically by display name.
      * @return List of LanguageItems.
      */
     public Collection<LanguageItem> getAlwaysTranslateLanguageItems() {
         // Get the latest always translate list from native. This list has no guaranteed order.
         List<String> codes = TranslateBridge.getAlwaysTranslateLanguages();
         TreeSet<LanguageItem> results = new TreeSet(LanguageItem.COMPARE_BY_DISPLAY_NAME);
         for (String code : codes) {
             if (mLanguagesMap.containsKey(code)) results.add(mLanguagesMap.get(code));
         }
         return results;
     }

     /**
      * Get a list of LanguageItems that the user has set to never prompt for translation. The list
      * is sorted alphabetically by display name.
      * @return List of LanguageItems.
      */
     public Collection<LanguageItem> getNeverTranslateLanguageItems() {
         // Get the latest never translate list from native. This list has no guaranteed order.
         List<String> codes = TranslateBridge.getNeverTranslateLanguages();
         TreeSet<LanguageItem> results = new TreeSet(LanguageItem.COMPARE_BY_DISPLAY_NAME);
         for (String code : codes) {
             if (mLanguagesMap.containsKey(code)) results.add(mLanguagesMap.get(code));
         }
         return results;
     }

     /**
      * Get a LanguageItem given the iso639 locale code (e.g. en-US). If no match is found the base
      * language is checked (e.g. "en" for "en-AU"). If there is still no match null is returned.
      * @return LanguageItem or null if none found
      */
     public LanguageItem getLanguageItem(String localeCode) {
         if (TextUtils.equals(localeCode, AppLocaleUtils.SYSTEM_LANGUAGE_VALUE)) {
             return LanguageItem.makeSystemDefaultLanguageItem();
         }
         LanguageItem result = mLanguagesMap.get(localeCode);
         if (result != null) return result;

         String baseLanguage = LocaleUtils.toLanguage(localeCode);
         return mLanguagesMap.get(baseLanguage);
     }

     /**
      * Add a language to the current user's accept languages.
      * @param code The language code to remove.
      */
     public void addToAcceptLanguages(String code) {
         TranslateBridge.updateUserAcceptLanguages(code, true /* is_add */);
         notifyAcceptLanguageObserver();
     }

     /**
      * Remove a language from the current user's accept languages.
      * @param code The language code to remove.
      */
     public void removeFromAcceptLanguages(String code) {
         TranslateBridge.updateUserAcceptLanguages(code, false /* is_add */);
         notifyAcceptLanguageObserver();
     }

     /**
      * Move a language's position in the user's accept languages list.
      * @param code The language code to move.
      * @param offset The offset from the original position.
      *               Negative value means up and positive value means down.
      * @param reload  Whether to reload the language list.
      */
     public void moveLanguagePosition(String code, int offset, boolean reload) {
         if (offset == 0) return;

         TranslateBridge.moveAcceptLanguage(code, offset);
         recordAction(LanguageSettingsActionType.LANGUAGE_LIST_REORDERED);
         if (reload) notifyAcceptLanguageObserver();
     }

     /**
      * Sets the preference order of the user's accepted languages to the provided order.
      *
      * @param codes The new order for the user's languages.
      * @param reload True iff the language list should be reloaded.
      */
     public void setOrder(String[] codes, boolean reload) {
         TranslateBridge.setLanguageOrder(codes);
         recordAction(LanguageSettingsActionType.LANGUAGE_LIST_REORDERED);
         if (reload) notifyAcceptLanguageObserver();
     }

     /**
      * Called to get all languages available in chrome.
      * @return A map of language code to {@code LanguageItem} for all available languages.
      */
     public Map<String, LanguageItem> getLanguageMap() {
         return mLanguagesMap;
     }

     /**
      * Get the static instance of ChromePreferenceManager if it exists else create it.
      * @return the LanguagesManager singleton.
      */
     public static LanguagesManager getInstance() {
         if (sManager == null) sManager = new LanguagesManager();
         return sManager;
     }

     /**
      * Called to release unused resources.
      */
     public static void recycle() {
         sManager = null;
     }

     /**
      * Record language settings page impression.
      */
     public static void recordImpression(@LanguageSettingsPageType int pageType) {
         RecordHistogram.recordEnumeratedHistogram(
                 "LanguageSettings.PageImpression", pageType, LanguageSettingsPageType.NUM_ENTRIES);
     }

     /**
      * Record actions taken on language settings page.
      */
     public static void recordAction(@LanguageSettingsActionType int actionType) {
         RecordHistogram.recordEnumeratedHistogram(
                 "LanguageSettings.Actions", actionType, LanguageSettingsActionType.NUM_ENTRIES);
     }
 }
	// Copyright 2017 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.

	package org.chromium.chrome.browser.language.settings;

	import android.text.TextUtils;

	import androidx.annotation.IntDef;
	import androidx.core.util.Predicate;

	import org.chromium.base.LocaleUtils;
	import org.chromium.base.metrics.RecordHistogram;
	import org.chromium.chrome.browser.language.AppLocaleUtils;
	import org.chromium.chrome.browser.translate.TranslateBridge;

	import java.lang.annotation.Retention;
	import java.lang.annotation.RetentionPolicy;
	import java.util.ArrayList;
	import java.util.Arrays;
	import java.util.Collection;
	import java.util.HashSet;
	import java.util.LinkedHashMap;
	import java.util.LinkedHashSet;
	import java.util.List;
	import java.util.Map;
	import java.util.TreeSet;

	/**
	* Manages languages details for languages settings.
	*
	*The LanguagesManager is responsible for fetching languages details from native.
	*/
	public class LanguagesManager {
	/**
	* An observer interface that allows other classes to know when the accept language list is
	* updated in native side.
	*/
	interface AcceptLanguageObserver {
	/**
	* Called when the accept languages for the current user are updated.
	*/
	void onDataUpdated();
	}

	// Constants used to log UMA enum histogram, must stay in sync with
	// LanguageSettingsActionType. Further actions can only be appended, existing
	// entries must not be overwritten.
	@IntDef({LanguageSettingsActionType.LANGUAGE_ADDED, LanguageSettingsActionType.LANGUAGE_REMOVED,
	LanguageSettingsActionType.DISABLE_TRANSLATE_GLOBALLY,
	LanguageSettingsActionType.ENABLE_TRANSLATE_GLOBALLY,
	LanguageSettingsActionType.DISABLE_TRANSLATE_FOR_SINGLE_LANGUAGE,
	LanguageSettingsActionType.ENABLE_TRANSLATE_FOR_SINGLE_LANGUAGE,
	LanguageSettingsActionType.LANGUAGE_LIST_REORDERED,
	LanguageSettingsActionType.CHANGE_CHROME_LANGUAGE,
	LanguageSettingsActionType.CHANGE_TARGET_LANGUAGE,
	LanguageSettingsActionType.REMOVE_FROM_NEVER_TRANSLATE,
	LanguageSettingsActionType.ADD_TO_NEVER_TRANSLATE,
	LanguageSettingsActionType.REMOVE_FROM_ALWAYS_TRANSLATE,
	LanguageSettingsActionType.ADD_TO_ALWAYS_TRANSLATE,
	LanguageSettingsActionType.REMOVE_SITE_FROM_NEVER_TRANSLATE})
	@Retention(RetentionPolicy.SOURCE)
	@interface LanguageSettingsActionType {
	// int CLICK_ON_ADD_LANGUAGE = 1; // Removed M89
	int LANGUAGE_ADDED = 2;
	int LANGUAGE_REMOVED = 3;
	int DISABLE_TRANSLATE_GLOBALLY = 4;
	int ENABLE_TRANSLATE_GLOBALLY = 5;
	int DISABLE_TRANSLATE_FOR_SINGLE_LANGUAGE = 6;
	int ENABLE_TRANSLATE_FOR_SINGLE_LANGUAGE = 7;
	int LANGUAGE_LIST_REORDERED = 8;
	int CHANGE_CHROME_LANGUAGE = 9;
	int CHANGE_TARGET_LANGUAGE = 10;
	int REMOVE_FROM_NEVER_TRANSLATE = 11;
	int ADD_TO_NEVER_TRANSLATE = 12;
	int REMOVE_FROM_ALWAYS_TRANSLATE = 13;
	int ADD_TO_ALWAYS_TRANSLATE = 14;
	int REMOVE_SITE_FROM_NEVER_TRANSLATE = 15;
	int NUM_ENTRIES = 16;
	}

	// Constants used to log UMA enum histogram, must stay in sync with
	// LanguageSettingsPageType. Further actions can only be appended, existing
	// entries must not be overwritten.
	@IntDef({LanguageSettingsPageType.PAGE_MAIN,
	LanguageSettingsPageType.CONTENT_LANGUAGE_ADD_LANGUAGE,
	LanguageSettingsPageType.CHANGE_CHROME_LANGUAGE,
	LanguageSettingsPageType.ADVANCED_LANGUAGE_SETTINGS,
	LanguageSettingsPageType.CHANGE_TARGET_LANGUAGE,
	LanguageSettingsPageType.LANGUAGE_OVERFLOW_MENU_OPENED,
	LanguageSettingsPageType.VIEW_NEVER_TRANSLATE_LANGUAGES,
	LanguageSettingsPageType.NEVER_TRANSLATE_ADD_LANGUAGE,
	LanguageSettingsPageType.VIEW_ALWAYS_TRANSLATE_LANGUAGES,
	LanguageSettingsPageType.ALWAYS_TRANSLATE_ADD_LANGUAGE,
	LanguageSettingsPageType.VIEW_NEVER_TRANSLATE_SITES})
	@Retention(RetentionPolicy.SOURCE)
	@interface LanguageSettingsPageType {
	int PAGE_MAIN = 0;
	int CONTENT_LANGUAGE_ADD_LANGUAGE = 1;
	// int LANGUAGE_DETAILS = 2; // iOS only
	int CHANGE_CHROME_LANGUAGE = 3;
	int ADVANCED_LANGUAGE_SETTINGS = 4;
	int CHANGE_TARGET_LANGUAGE = 5;
	int LANGUAGE_OVERFLOW_MENU_OPENED = 6;
	int VIEW_NEVER_TRANSLATE_LANGUAGES = 7;
	int NEVER_TRANSLATE_ADD_LANGUAGE = 8;
	int VIEW_ALWAYS_TRANSLATE_LANGUAGES = 9;
	int ALWAYS_TRANSLATE_ADD_LANGUAGE = 10;
	int VIEW_NEVER_TRANSLATE_SITES = 11;
	int NUM_ENTRIES = 12;
	}

	// Int keys to determine the list of potential languages for different language preferences.
	@IntDef({LanguageListType.ACCEPT_LANGUAGES, LanguageListType.UI_LANGUAGES,
	LanguageListType.TARGET_LANGUAGES, LanguageListType.NEVER_LANGUAGES,
	LanguageListType.ALWAYS_LANGUAGES})
	@Retention(RetentionPolicy.SOURCE)
	@interface LanguageListType {
	int ACCEPT_LANGUAGES = 0; // Default
	int UI_LANGUAGES = 1;
	int TARGET_LANGUAGES = 2;
	int NEVER_LANGUAGES = 3;
	int ALWAYS_LANGUAGES = 4;
	}

	private static LanguagesManager sManager;

	private final Map<String, LanguageItem> mLanguagesMap;

	private AcceptLanguageObserver mObserver;

	private LanguagesManager() {
	// Get all language data from native.
	mLanguagesMap = new LinkedHashMap<>();
	for (LanguageItem item : TranslateBridge.getChromeLanguageList()) {
	mLanguagesMap.put(item.getCode(), item);
	}
	}

	private void notifyAcceptLanguageObserver() {
	if (mObserver != null) mObserver.onDataUpdated();
	}

	/**
	* Sets the observer tracking the user accept languages changes.
	*/
	public void setAcceptLanguageObserver(AcceptLanguageObserver observer) {
	mObserver = observer;
	}

	/**
	* @return A list of LanguageItems for the current user's accept languages.
	*/
	public List<LanguageItem> getUserAcceptLanguageItems() {
	// Always read the latest user accept language code list from native.
	List<String> codes = TranslateBridge.getUserLanguageCodes();

	List<LanguageItem> results = new ArrayList<>();
	// Keep the same order as accept language codes list.
	for (String code : codes) {
	// Check language code and only languages supported on Android are added in.
	if (mLanguagesMap.containsKey(code)) results.add(mLanguagesMap.get(code));
	}
	return results;
	}

	/**
	* Get the list of potential languages to show in the {@link AddLanguageFragment} based on which
	* list or preference a language will be added to. By default the potential languages for the
	* Accept-Language list is returned.
	* @param LanguageListType key to select which languages to get.
	* @return A list of LanguageItems to choose from for the given preference.
	*/
	public List<LanguageItem> getPotentialLanguages(@LanguageListType int potentialLanguages) {
	switch (potentialLanguages) {
	case LanguageListType.ALWAYS_LANGUAGES:
	return getPotentialTranslateLanguages(
	TranslateBridge.getAlwaysTranslateLanguages());
	case LanguageListType.NEVER_LANGUAGES:
	return getPotentialTranslateLanguages(TranslateBridge.getNeverTranslateLanguages());
	case LanguageListType.TARGET_LANGUAGES:
	return getPotentialTranslateLanguages(
	Arrays.asList(TranslateBridge.getTargetLanguageForChromium()));
	case LanguageListType.UI_LANGUAGES:
	return getPotentialUiLanguages();
	case LanguageListType.ACCEPT_LANGUAGES:
	return getPotentialAcceptLanguages();
	default:
	assert false : "No valid LanguageListType";
	return null;
	}
	}

	/**
	* Get a list of LanguageItems that can be used as a Translate language but excluding
	* \|codesToSkip\|. The current Accept-Languages are added to the front of the list.
	* @param codesToSkip Collection of String language codes to exclude from the list.
	* @return List of LanguageItems.
	*/
	private List<LanguageItem> getPotentialTranslateLanguages(Collection<String> codesToSkip) {
	HashSet<String> codesToSkipSet = new HashSet<String>(codesToSkip);
	LinkedHashSet<LanguageItem> results = new LinkedHashSet<>();
	// Filter for translatable languages not in \|codesToSkipSet\|.
	Predicate<LanguageItem> filter = (item) -> {
	return item.isSupportedBaseLanguage() && !codesToSkipSet.contains(item.getCode());
	};
	addItemsToResult(results, getUserAcceptLanguageItems(), filter);
	addItemsToResult(results, mLanguagesMap.values(), filter);
	return new ArrayList<>(results);
	}

	/**
	* Get a list of potential LanguageItems Chrome UI languages excluding the current UI language.
	* The current Accept-Languages are added to the front of the the list.
	* @return List of LanguageItems.
	*/
	public List<LanguageItem> getPotentialUiLanguages() {
	LinkedHashSet<LanguageItem> results = new LinkedHashSet<>();
	LanguageItem currentUiLanguage = getLanguageItem(AppLocaleUtils.getAppLanguagePref());

	// Add the system default language if an override language is set.
	if (!currentUiLanguage.isSystemDefault()) {
	results.add(LanguageItem.makeSystemDefaultLanguageItem());
	}

	// Filter for UI languages that are not the current UI language.
	Predicate<LanguageItem> filter = (item) -> {
	return item.isUISupported() && !item.equals(currentUiLanguage);
	};
	addItemsToResult(results, getUserAcceptLanguageItems(), filter);
	addItemsToResult(results, mLanguagesMap.values(), filter);
	return new ArrayList<>(results);
	}

	/**
	* Get a list of potential Accept-Languages excluding the current Accept-Languages.
	* @return A list of LanguageItems, excluding the current user's accept languages.
	*/
	private List<LanguageItem> getPotentialAcceptLanguages() {
	// Always read the latest user accept language code list from native.
	HashSet<String> codesToSkip = new HashSet(TranslateBridge.getUserLanguageCodes());
	LinkedHashSet<LanguageItem> results = new LinkedHashSet<>();
	addItemsToResult(
	results, mLanguagesMap.values(), (item) -> !codesToSkip.contains(item.getCode()));
	return new ArrayList<>(results);
	}

	/**
	* Add LanguageItems in \|items\| to \|results\| keeping their order and excluding items that match
	* \|filter\|.
	* @param results LinkedHashSet of LanguageItems to add items to.
	* @param items Collection of LanguageItems to potentially add to results.
	* @param filter Predicate to return true for items that should be added to results.
	*/
	private void addItemsToResult(LinkedHashSet<LanguageItem> results,
	Collection<LanguageItem> items, Predicate<LanguageItem> filter) {
	for (LanguageItem item : items) {
	if (filter.test(item)) {
	results.add(item);
	}
	}
	}

	/**
	* Get a list of LanguageItems that the user has set to always translate. The list is sorted
	* alphabetically by display name.
	* @return List of LanguageItems.
	*/
	public Collection<LanguageItem> getAlwaysTranslateLanguageItems() {
	// Get the latest always translate list from native. This list has no guaranteed order.
	List<String> codes = TranslateBridge.getAlwaysTranslateLanguages();
	TreeSet<LanguageItem> results = new TreeSet(LanguageItem.COMPARE_BY_DISPLAY_NAME);
	for (String code : codes) {
	if (mLanguagesMap.containsKey(code)) results.add(mLanguagesMap.get(code));
	}
	return results;
	}

	/**
	* Get a list of LanguageItems that the user has set to never prompt for translation. The list
	* is sorted alphabetically by display name.
	* @return List of LanguageItems.
	*/
	public Collection<LanguageItem> getNeverTranslateLanguageItems() {
	// Get the latest never translate list from native. This list has no guaranteed order.
	List<String> codes = TranslateBridge.getNeverTranslateLanguages();
	TreeSet<LanguageItem> results = new TreeSet(LanguageItem.COMPARE_BY_DISPLAY_NAME);
	for (String code : codes) {
	if (mLanguagesMap.containsKey(code)) results.add(mLanguagesMap.get(code));
	}
	return results;
	}

	/**
	* Get a LanguageItem given the iso639 locale code (e.g. en-US). If no match is found the base
	* language is checked (e.g. "en" for "en-AU"). If there is still no match null is returned.
	* @return LanguageItem or null if none found
	*/
	public LanguageItem getLanguageItem(String localeCode) {
	if (TextUtils.equals(localeCode, AppLocaleUtils.SYSTEM_LANGUAGE_VALUE)) {
	return LanguageItem.makeSystemDefaultLanguageItem();
	}
	LanguageItem result = mLanguagesMap.get(localeCode);
	if (result != null) return result;

	String baseLanguage = LocaleUtils.toLanguage(localeCode);
	return mLanguagesMap.get(baseLanguage);
	}

	/**
	* Add a language to the current user's accept languages.
	* @param code The language code to remove.
	*/
	public void addToAcceptLanguages(String code) {
	TranslateBridge.updateUserAcceptLanguages(code, true /* is_add */);
	notifyAcceptLanguageObserver();
	}

	/**
	* Remove a language from the current user's accept languages.
	* @param code The language code to remove.
	*/
	public void removeFromAcceptLanguages(String code) {
	TranslateBridge.updateUserAcceptLanguages(code, false /* is_add */);
	notifyAcceptLanguageObserver();
	}

	/**
	* Move a language's position in the user's accept languages list.
	* @param code The language code to move.
	* @param offset The offset from the original position.
	* Negative value means up and positive value means down.
	* @param reload Whether to reload the language list.
	*/
	public void moveLanguagePosition(String code, int offset, boolean reload) {
	if (offset == 0) return;

	TranslateBridge.moveAcceptLanguage(code, offset);
	recordAction(LanguageSettingsActionType.LANGUAGE_LIST_REORDERED);
	if (reload) notifyAcceptLanguageObserver();
	}

	/**
	* Sets the preference order of the user's accepted languages to the provided order.
	*
	* @param codes The new order for the user's languages.
	* @param reload True iff the language list should be reloaded.
	*/
	public void setOrder(String[] codes, boolean reload) {
	TranslateBridge.setLanguageOrder(codes);
	recordAction(LanguageSettingsActionType.LANGUAGE_LIST_REORDERED);
	if (reload) notifyAcceptLanguageObserver();
	}

	/**
	* Called to get all languages available in chrome.
	* @return A map of language code to {@code LanguageItem} for all available languages.
	*/
	public Map<String, LanguageItem> getLanguageMap() {
	return mLanguagesMap;
	}

	/**
	* Get the static instance of ChromePreferenceManager if it exists else create it.
	* @return the LanguagesManager singleton.
	*/
	public static LanguagesManager getInstance() {
	if (sManager == null) sManager = new LanguagesManager();
	return sManager;
	}

	/**
	* Called to release unused resources.
	*/
	public static void recycle() {
	sManager = null;
	}

	/**
	* Record language settings page impression.
	*/
	public static void recordImpression(@LanguageSettingsPageType int pageType) {
	RecordHistogram.recordEnumeratedHistogram(
	"LanguageSettings.PageImpression", pageType, LanguageSettingsPageType.NUM_ENTRIES);
	}

	/**
	* Record actions taken on language settings page.
	*/
	public static void recordAction(@LanguageSettingsActionType int actionType) {
	RecordHistogram.recordEnumeratedHistogram(
	"LanguageSettings.Actions", actionType, LanguageSettingsActionType.NUM_ENTRIES);
	}
	}