title: puppeteer blank pdf generation
body: <p>I'm using this simple code to generate a pdf document from <a href="http://example.com/" rel="noreferrer">http://example.com/</a> 
  but I keep getting a blank pdf generated ... </p>
  
  <p>Am I missing something ?</p>
  
  <pre><code>const puppeteer = require('puppeteer');
  
  puppeteer.launch({ args: ['--no-sandbox', '--disable-setuid-sandbox'] }).then(function (browser) {
    browser.newPage().then(function (page) {
      page
        .goto('http://example.com/', { waitUntil:['domcontentloaded', 'networkidle0','load'] })
        .then(page.pdf({ path: 'result.pdf', format: 'letter' }))
        .then(() =&gt; {
          browser.close();
        })
    })
  })
  </code></pre>
  
  <p>I used the no-sandbox option because of kernel issues.</p>
  
  <p>I'm using CentOS 7 </p>