Bug 976142 - Print vc change events more clearly. r=yzen

accessible/src/jsat/Utils.jsm

@@ -433,6 +433,15 @@ this.Logger = {
       str += ' (' + stateStrings.item(0) + ')';
     }
 
+    if (aEvent.eventType == Events.VIRTUALCURSOR_CHANGED) {
+      let event = aEvent.QueryInterface(
+        Ci.nsIAccessibleVirtualCursorChangeEvent);
+      let pivot = aEvent.accessible.QueryInterface(
+        Ci.nsIAccessibleDocument).virtualCursor;
+      str += ' (' + this.accessibleToString(event.oldAccessible) + ' -> ' +
+	this.accessibleToString(pivot.position) + ')';
+    }
+
     return str;
   },