Bug 1529845 - Add a destroy for the MarkupContextMenu. r=rcaliman

Differential Revision: https://phabricator.services.mozilla.com/D20783

devtools/client/inspector/markup/markup-context-menu.js

@@ -36,6 +36,16 @@ class MarkupContextMenu {
     this.walker = this.inspector.walker;
   }
 
+  destroy() {
+    this.markup = null;
+    this.inspector = null;
+    this.selection = null;
+    this.target = null;
+    this.telemetry = null;
+    this.toolbox = null;
+    this.walker = null;
+  }
+
   show(event) {
     if (!(event.originalTarget instanceof Element) ||
         event.originalTarget.closest("input[type=text]") ||

devtools/client/inspector/markup/markup.js

@@ -2029,6 +2029,11 @@ MarkupView.prototype = {
 
     this._hoveredContainer = null;
 
+    if (this._contextMenu) {
+      this._contextMenu.destroy();
+      this._contextMenu = null;
+    }
+
     if (this._eventDetailsTooltip) {
       this._eventDetailsTooltip.destroy();
       this._eventDetailsTooltip = null;