DevTools: [lighthouse] Implement performance metrics filmstrip

third_party/WebKit/Source/devtools/front_end/audits2_worker/Audits2Service.js

 // Copyright (c) 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 /**
  * @interface
  */
 class LighthousePort {
   /**
    * @param {!string} eventName, 'message', 'close'
    * @param {function(string|undefined)} cb
@@ skipping 27 matching lines @@
 
   /**
    * @return {!Promise<!ReportRenderer.ReportJSON>}
    */
   start(params) {
     self.listenForStatus(message => {
       this.statusUpdate(message[1]);
     });
 
     return Promise.resolve()
-      .then(_ => self.runLighthouseInWorker(this, params.url, undefined, params.categoryIDs))
-      .then(/** @type {!ReportRenderer.ReportJSON} */ result => result)
-      .catchException(null);
+        .then(_ => self.runLighthouseInWorker(this, params.url, undefined, params.categoryIDs))
+        .then(/** @type {!ReportRenderer.ReportJSON} */ result => {
+          // Filter out artifacts except for screenshots in traces to minimize report size.
+          var traces = result['artifacts']['traces'];
+          for (var pass in traces) {
+            traces[pass]['traceEvents'] =
+                traces[pass]['traceEvents'].filter(e => e['cat'] === 'disabled-by-default-devtools.screenshot');
+          }
+          result['artifacts'] = {traces: traces};
+          return result;
+        })
+        .catchException(null);
   }
 
   /**
    * @return {!Promise}
    */
   stop() {
     this.close();
     return Promise.resolve();
   }
 
@@ skipping 44 matching lines @@
 };
 
 // Make lighthouse and traceviewer happy.
 global = self;
 global.isVinn = true;
 global.document = {};
 global.document.documentElement = {};
 global.document.documentElement.style = {
   WebkitAppearance: 'WebkitAppearance'
 };