Bug 1484914 - Never append duplicate access key hints r=bzbarsky

On macOS, access keys are not visually observable.

On Linux and Windows, access keys are underlined.
Moreover, if intl.menuitems.alwaysappendaccesskeys is set, the access
key is always appended as "(X)", optionally preceded by a space, where X
is the uppercased version of the access key.

This commit updates the logic to not append a new "(X)" if this expected
suffix is already present at the end of the label.

Differential Revision: https://phabricator.services.mozilla.com/D3996

--HG--
extra : moz-landing-system : lando

layout/xul/nsTextBoxFrame.cpp

@@ -838,7 +838,7 @@ nsTextBoxFrame::UpdateAccessTitle()
     /*
      * Note that if you change appending access key label spec,
      * you need to maintain same logic in following methods. See bug 324159.
-     * toolkit/content/commonDialog.js (setLabelForNode)
+     * toolkit/components/prompts/src/CommonDialog.jsm (setLabelForNode)
      * toolkit/content/widgets/text.xml (formatAccessKey)
      */
     int32_t menuAccessKey;
@@ -861,6 +861,11 @@ nsTextBoxFrame::UpdateAccessTitle()
         return;
     }
 
+    if (StringEndsWith(mTitle, accessKeyLabel)) {
+      // Never append another "(X)" if the title already ends with "(X)".
+      return;
+    }
+
     const nsDependentString& kEllipsis = nsContentUtils::GetLocalizedEllipsis();
     uint32_t offset = mTitle.Length();
     if (StringEndsWith(mTitle, kEllipsis)) {

toolkit/components/passwordmgr/nsLoginManagerPrompter.js

@@ -1061,7 +1061,7 @@ LoginManagerPrompter.prototype = {
     // Ugh. We can't use the strings from the popup window, because they
     // have the access key marked in the string (eg "Mo&zilla"), along
     // with some weird rules for handling access keys that do not occur
-    // in the string, for L10N. See commonDialog.js's setLabelForNode().
+    // in the string, for L10N. See CommonDialog.jsm's setLabelForNode().
     var neverButtonText =
           this._getLocalizedString("notifyBarNeverRememberButtonText2");
     var neverButtonAccessKey =

toolkit/content/widgets/text.xml

@@ -137,6 +137,8 @@
                 accessKeyIndex =
                   labelText.toUpperCase().indexOf(accessKey.toUpperCase());
               }
+            } else if (labelText.endsWith(`(${accessKey.toUpperCase()})`)) {
+              accessKeyIndex = labelText.length - (1 + accessKey.length); // = index of accessKey.
             }
 
             const HTML_NS = "http://www.w3.org/1999/xhtml";