Issue 4544 - Consider platformHTMLBindings.xml when detecting available keyboard shortcuts

lib/keySelector.js

Index: lib/keySelector.js
===================================================================
--- a/lib/keySelector.js
+++ b/lib/keySelector.js
@@ -7,16 +7,29 @@ Cu.import("resource://gre/modules/Servic
 let validModifiers = Object.create(null);
 validModifiers.ACCEL = null;
 validModifiers.CTRL = "control";
 validModifiers.CONTROL = "control";
 validModifiers.SHIFT = "shift";
 validModifiers.ALT = "alt";
 validModifiers.META = "meta";
 
+let bindingsKeys = null;
+(function()
+{
+  let request = new XMLHttpRequest();
+  request.open("GET", "chrome://global/content/platformHTMLBindings.xml");
+  request.addEventListener("load", () =>
+  {
+    bindingsKeys = request.responseXML.getElementsByTagName("handler");
+  });
+  request.send();
+})();
+
+
 /**
  * Sets the correct value of validModifiers.ACCEL.
  */
 function initAccelKey()
 {
   validModifiers.ACCEL = "control";
   try
   {
@@ -60,17 +73,19 @@ KeySelector.prototype =
    */
   _initExistingShortcuts: function(/**ChromeWindow*/ window)
   {
     if (!validModifiers.ACCEL)
       initAccelKey();
 
     this._existingShortcuts = Object.create(null);
 
-    let keys = window.document.getElementsByTagName("key");
+    let keys = Array.prototype.slice.apply(window.document.getElementsByTagName("key"));
+    if (bindingsKeys)
+      keys.push.apply(keys, bindingsKeys);
     for (let i = 0; i < keys.length; i++)
     {
       let key = keys[i];
       let keyData =
       {
         shift: false,
         meta: false,
         alt: false,