title: Cookie not set in iFrame
body: <p>Scenario:</p>
  <p>I have parent site A domain A that embeds an iframe with domain B...note that I have control of both sites. Im calling postMessage from site A that posts some information to be stored as cookie in iframe domain B. The iFrame will listen to the postMessage event and set cookie accordingly.</p>
  <p>Domain A:</p>
  <pre><code> var frame = document.getElementById('exampleFrame');
   frame.contentWindow.postMessage({&quot;age&quot;:28}, '*');
  </code></pre>
  <p>Embedded iframe domain B:</p>
  <pre><code>window.addEventListener('message', messageReceivedEvent, false);
  
  function messageReceivedEvent(e) {
     document.cookie(&quot;age=&quot; + e.data.age + &quot;;&quot;);
     console.log(document.cookie);
  }
  </code></pre>
  <blockquote>
  <p>console.log(document.cookie) returns nothing</p>
  </blockquote>
  <p>The issue here is that, once i set the cookie in the <strong>messageReceivedEvent</strong>, it seems like the cookie is not stored in domain B. Did I missed out something?</p>
  <blockquote>
  <p>Note: This issue only happened in latest Google Chrome version, Firefox works fine.</p>
  </blockquote>