title: Chrome webgl rendering / flashing issue
body: <p>I try to get a unity => webgl export working on google chrome browser.</p>
  
  <p>It works fine on firefox but on Chrome the background is not transparent and seems dirty, sometimes it even flickers super fast (very dangerous for people suffering from epilepsy)</p>
  
  <p>This is the code that should do the transparent background:</p>
  
  <pre><code>  var LibraryGLClear = {
        glClear: function(mask)
        {
            if (mask == 0x00004000)
            {
                var v = GLctx.getParameter(GLctx.COLOR_WRITEMASK);
                if (!v[0] &amp;&amp; !v[1] &amp;&amp; !v[2] &amp;&amp; v[3])
                    // We are trying to clear alpha only -- skip.
                    return;
            }
            GLctx.clear(mask);
        }
    };
  
    mergeInto(LibraryManager.library, LibraryGLClear);
  </code></pre>
  
  <p>the code was taken from here: <a href="https://answers.unity.com/questions/1069255/embed-webgl-in-webpage-with-transparent-background.html" rel="nofollow noreferrer">https://answers.unity.com/questions/1069255/embed-webgl-in-webpage-with-transparent-background.html</a></p>
  
  <p><strong>With</strong> Transparency Code: <a href="https://youtu.be/qpTq73ZL5_c" rel="nofollow noreferrer">https://youtu.be/qpTq73ZL5_c</a> (do not watch if fast changing images can trigger epilepsy for you)</p>
  
  <p>I thought it was caused by the transparency code. Unfortunately, it is not the root cause because I bundled it without the transparent code and got a similar issue:</p>
  
  <p><strong>Without</strong>: <a href="https://youtu.be/271mZsizvps" rel="nofollow noreferrer">https://youtu.be/271mZsizvps</a></p>
  
  <p>Is there maybe a special setting in Unity I could play with?
  Do you have the same issue?</p>
  
  <p>Please help, thank you!</p>