Cookies are not working in an iframe in Android Webview
<p>One user of my Webview based browser app reported an issue with embedding Google Calendar in an iframe. It looks like the iframe loaded by Android Webview (latest version from Google Play, tested with Android 6) can't read or set any cookies.</p>

<p>The issue is not present in Google Chrome on the same device. It seems to be related to Android Webview only.</p>

<p>I can reproduce the issue with following site.</p>

<p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
<div class="snippet-code">
<pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;!DOCTYPE html&gt;
    &lt;html&gt;
    &lt;head&gt;
    &lt;meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=no" /&gt;
    &lt;/head&gt;
    &lt;body&gt;
    &lt;a href="http://www.w3schools.com/js/js_cookies.asp"&gt;Cookies Management&lt;/a&gt;
    &lt;br&gt;&lt;br&gt;
    &lt;iframe style="margin-top: 30px; border-width: 1px;" src="http://www.w3schools.com/js/js_cookies.asp" width="400" height="672" scrolling="yes"&gt;&lt;/iframe&gt;
    &lt;/body&gt;
    &lt;/html&gt;</code></pre>
</div>
</div>
</p>

<p>If you open the cookie site via link in the main frame you can set/read cookies by the buttons "Create Cookie..." or "Display All Cookies". In the iframe however displaying all cookies always returns an empty result. Even if you create a cookie in the iframe displaying all cookies then gets an empty result.</p>

<p>Are there any Webview settings affecting this behaviour?</p>