text: /**
   * @license
   * Copyright 2016 Google Inc. All rights reserved.
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  'use strict';
  
  const ComputedArtifact = require('./computed-artifact');
  const DevtoolsTimelineModel = require('../../lib/traces/devtools-timeline-model');
  
  class ScreenshotFilmstrip extends ComputedArtifact {
  
    get name() {
      return 'Screenshots';
    }
  
    fetchScreenshot(frame) {
      return frame
        .imageDataPromise()
        .then(data => 'data:image/jpg;base64,' + data);
    }
  
    /**
     * @param {{traceEvents: !Array}} trace
     * @return {!Promise}
    */
    compute_(trace) {
      const model = new DevtoolsTimelineModel(trace.traceEvents);
      const filmStripFrames = model.filmStripModel().frames();
  
      const frameFetches = filmStripFrames.map(frame => this.fetchScreenshot(frame));
      return Promise.all(frameFetches).then(images => {
        const result = filmStripFrames.map((frame, i) => ({
          timestamp: frame.timestamp,
          datauri: images[i]
        }));
        return result;
      });
    }
  }
  
  module.exports = ScreenshotFilmstrip;
  