Typecheck lighthouse/LighthousePanel.js with TypeScript

R=aerotwist@chromium.org

Bug: 1011811
Change-Id: I04033020df768cd58c5a6a4de2ee3de314b6ed3d
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/2521136
Commit-Queue: Tim van der Lippe <tvanderlippe@chromium.org>
Auto-Submit: Tim van der Lippe <tvanderlippe@chromium.org>
Reviewed-by: Paul Lewis <aerotwist@chromium.org>
diff --git a/front_end/lighthouse/LighthouseReportRenderer.js b/front_end/lighthouse/LighthouseReportRenderer.js
index e90f956..c495951 100644
--- a/front_end/lighthouse/LighthouseReportRenderer.js
+++ b/front_end/lighthouse/LighthouseReportRenderer.js
@@ -25,6 +25,12 @@
  */
 export class LighthouseReportRenderer extends self.ReportRenderer {
   /**
+   * @param {!DOM} dom
+   */
+  constructor(dom) {
+    super(dom);
+  }
+  /**
    * @param {!Element} el Parent element to render the report into.
    * @param {!ReportRenderer.RunnerResultArtifacts=} artifacts
    */
@@ -133,14 +139,16 @@
   }
 
   /**
-   * @param {?function()} beforePrint
+   * @override
+   * @param {?function():void} beforePrint
    */
   setBeforePrint(beforePrint) {
     this._beforePrint = beforePrint;
   }
 
   /**
-   * @param {?function()} afterPrint
+   * @override
+   * @param {?function():void} afterPrint
    */
   setAfterPrint(afterPrint) {
     this._afterPrint = afterPrint;