Bug 944947 - automatically hyphenate labels for items in Australis' menupanel, r=MattN

browser/components/customizableui/content/panelUI.js

@@ -207,6 +207,8 @@ const PanelUI = {
       return this._readyPromise;
     }
     this._readyPromise = Task.spawn(function() {
+      this.contents.setAttributeNS("http://www.w3.org/XML/1998/namespace", "lang",
+                                   getLocale());
       if (!this._scrollWidth) {
         // In order to properly center the contents of the panel, while ensuring
         // that we have enough space on either side to show a scrollbar, we have to
@@ -412,3 +414,25 @@ const PanelUI = {
     this.removeEventListener("command", PanelUI.onCommandHandler);
   }
 };
+
+/**
+ * Gets the currently selected locale for display.
+ * @return  the selected locale or "en-US" if none is selected
+ */
+function getLocale() {
+  try {
+    let locale = Services.prefs.getComplexValue(PREF_SELECTED_LOCALE,
+                                                Ci.nsIPrefLocalizedString);
+    if (locale)
+      return locale;
+  }
+  catch (e) { }
+
+  try {
+    return Services.prefs.getCharPref(PREF_SELECTED_LOCALE);
+  }
+  catch (e) { }
+
+  return "en-US";
+}
+

browser/themes/shared/customizableui/panelUIOverlay.inc.css

@@ -77,6 +77,7 @@ toolbaritem[cui-areatype="menu-panel"][sdkstylewidget="true"]:not(.panel-wide-it
   font-size: 10px;
   margin: 2px 0 0;
   text-align: center;
+  -moz-hyphens: auto;
 }
 
 #wrapper-edit-controls:-moz-any([place="palette"],[place="panel"]) > #edit-controls,