Add 'onHighlight' optional event callback mechanism for better extensibility features in hint providers (#14140)

Author: swmitra

src/editor/CodeHintList.js

@@ -150,6 +150,10 @@ define(function (require, exports, module) {
 
             $item.find("a").addClass("highlight");
             ViewUtils.scrollElementIntoView($view, $item, false);
+
+            if (this.handleHighlight) {
+                this.handleHighlight($item.find("a"));
+            }
         }
     };
 
@@ -544,6 +548,15 @@ define(function (require, exports, module) {
         this.handleSelect = callback;
     };
 
+    /**
+      * Set the hint list highlight callback function
+      *
+      * @param {Function} callback
+      */
+    CodeHintList.prototype.onHighlight = function (callback) {
+        this.handleHighlight = callback;
+    };
+
     /**
      * Set the hint list closure callback function
      *

src/editor/CodeHintManager.js

@@ -507,6 +507,12 @@ define(function (require, exports, module) {
 
             sessionEditor = editor;
             hintList = new CodeHintList(sessionEditor, insertHintOnTab, maxCodeHints);
+            hintList.onHighlight(function ($hint) {
+                // If the current hint provider listening for hint item highlight change
+                if (sessionProvider.onHighlight) {
+                    sessionProvider.onHighlight($hint);
+                }
+            });
             hintList.onSelect(function (hint) {
                 var restart = sessionProvider.insertHint(hint),
                     previousEditor = sessionEditor;