Bug 1336281 followup - Unify the JS-callable and C++-only versions of LocaleService::GetAppLocale, and declare it as a read-only attribute in IDL. r=gandalf

intl/locale/LocaleService.cpp

@@ -60,15 +60,6 @@ LocaleService::GetAppLocales(nsTArray<nsCString>& aRetVal)
   aRetVal = mAppLocales;
 }
 
-void
-LocaleService::GetAppLocale(nsACString& aRetVal)
-{
-  if (mAppLocales.IsEmpty()) {
-    ReadAppLocales(mAppLocales);
-  }
-  aRetVal = mAppLocales[0];
-}
-
 void
 LocaleService::Refresh()
 {
@@ -111,8 +102,11 @@ LocaleService::GetAppLocales(JSContext* aCtx, JS::MutableHandleValue aRetVal)
 }
 
 NS_IMETHODIMP
-LocaleService::GetAppLocale(JSContext* aCtx, nsACString& aRetVal)
+LocaleService::GetAppLocale(nsACString& aRetVal)
 {
-  GetAppLocale(aRetVal);
+  if (mAppLocales.IsEmpty()) {
+    ReadAppLocales(mAppLocales);
+  }
+  aRetVal = mAppLocales[0];
   return NS_OK;
 }

intl/locale/LocaleService.h

@@ -57,30 +57,13 @@ public:
    * Example: ["en-US", "de", "pl", "sr-Cyrl", "zh-Hans-HK"]
    *
    * Usage:
-   * nsTArray<nsCString> appLocales;
-   * LocaleService::GetInstance()->GetAppLocales(appLocales);
+   *   nsTArray<nsCString> appLocales;
+   *   LocaleService::GetInstance()->GetAppLocales(appLocales);
+   *
+   * (See mozILocaleService.idl for a JS-callable version of this.)
    */
   void GetAppLocales(nsTArray<nsCString>& aRetVal);
 
-  /**
-   * Returns the best locale that the application should be localized to.
-   *
-   * The result is a valid locale IDs and it should be
-   * used for all APIs that do not handle language negotiation.
-   *
-   * Where possible, GetAppLocales should be preferred over this API and
-   * all callsites should handle some form of "best effort" language
-   * negotiation to respect user preferences in case the use case does
-   * not have data for the first locale in the list.
-   *
-   * Example: "zh-Hans-HK"
-   *
-   * Usage:
-   * nsAutoCString appLocale;
-   * LocaleService::GetInstance()->GetAppLocale(appLocale);
-   */
-  void GetAppLocale(nsACString& aRetVal);
-
   /**
    * Triggers a refresh of the language negotiation process.
    *

intl/locale/mozILocaleService.idl

@@ -16,6 +16,32 @@
 [scriptable, uuid(C27F8983-B48B-4D1A-92D7-FEB8106F212D)]
 interface mozILocaleService : nsISupports
 {
+  /**
+   * Returns a list of locales that the application should be localized to.
+   *
+   * The result is a sorted list of valid locale IDs and it should be
+   * used for all APIs that accept list of locales, like ECMA402 and L10n APIs.
+   *
+   * This API always returns at least one locale.
+   *
+   * Example: ["en-US", "de", "pl", "sr-Cyrl", "zh-Hans-HK"]
+   *
+   * (See LocaleService.h for a more C++-friendly version of this.)
+   */
   [implicit_jscontext] jsval getAppLocales();
-  [implicit_jscontext] ACString getAppLocale();
+
+  /**
+   * Returns the best locale that the application should be localized to.
+   *
+   * The result is a valid locale ID and it should be
+   * used for all APIs that do not handle language negotiation.
+   *
+   * Where possible, getAppLocales() should be preferred over this API and
+   * all callsites should handle some form of "best effort" language
+   * negotiation to respect user preferences in case the use case does
+   * not have data for the first locale in the list.
+   *
+   * Example: "zh-Hans-HK"
+   */
+  ACString getAppLocale();
 };