Bug 1620280 - [devtools] Prevent showing/hiding highlighters when the panels are already destroyed. r=jdescottes

browser_animation_animation-target_select.js was failing on debug builds because of exception during test ends.

Differential Revision: https://phabricator.services.mozilla.com/D91892

devtools/client/inspector/boxmodel/box-model.js

@@ -233,6 +233,11 @@ BoxModel.prototype = {
    * Hides the box-model highlighter on the currently selected element.
    */
   onHideBoxModelHighlighter() {
+    // As React components aren't destroyed when the panel closes,
+    // this function may still be called and throw because of destroyed fronts.
+    if (!this.inspector) {
+      return;
+    }
     this.inspector.highlighters.hideHighlighterType(
       this.inspector.highlighters.TYPES.BOXMODEL
     );

devtools/client/inspector/inspector.js

@@ -1927,6 +1927,11 @@ Inspector.prototype = {
    *         Options passed to the highlighter actor.
    */
   onShowBoxModelHighlighterForNode(nodeFront, options) {
+    // As React components aren't destroyed when the panel closes,
+    // this function may still be called and throw because of destroyed fronts.
+    if (this._destroyed) {
+      return;
+    }
     this.highlighters.showHighlighterTypeForNode(
       this.highlighters.TYPES.BOXMODEL,
       nodeFront,