Add code to resume blocked AudioContexts

src/shell.html

@@ -85,7 +85,8 @@ jwE50AGjLCVuS8Yt4H7OgZLKK5EKOsLviEWJSL/+0uMi7gLUSBseYwqEbXvSHCec1CJvZPyHCmYQffaB
         margin: 0; 
         margin-top: 20px; 
         margin-left: 20px;
-        display: inline-block; vertical-align: top;
+        display: inline-block;
+        vertical-align: top;
         -webkit-animation: rotation .8s linear infinite;
         -moz-animation: rotation .8s linear infinite;
         -o-animation: rotation .8s linear infinite;
@@ -253,8 +254,7 @@ jwE50AGjLCVuS8Yt4H7OgZLKK5EKOsLviEWJSL/+0uMi7gLUSBseYwqEbXvSHCec1CJvZPyHCmYQffaB
                     progressElement.value = null;
                     progressElement.max = null;
                     progressElement.hidden = true;
-                    
-                    if (!text) spinnerElement.hidden = true;
+                    if (!text) spinnerElement.style.display = 'none';
                 }
                 
                 statusElement.innerHTML = text;
@@ -263,7 +263,8 @@ jwE50AGjLCVuS8Yt4H7OgZLKK5EKOsLviEWJSL/+0uMi7gLUSBseYwqEbXvSHCec1CJvZPyHCmYQffaB
             monitorRunDependencies: function(left) {
                 this.totalDependencies = Math.max(this.totalDependencies, left);
                 Module.setStatus(left ? 'Preparing... (' + (this.totalDependencies-left) + '/' + this.totalDependencies + ')' : 'All downloads complete.');
-            }
+            },
+            //noInitialRun: true
         };
         
         Module.setStatus('Downloading...');
@@ -274,6 +275,48 @@ jwE50AGjLCVuS8Yt4H7OgZLKK5EKOsLviEWJSL/+0uMi7gLUSBseYwqEbXvSHCec1CJvZPyHCmYQffaB
             Module.setStatus = function(text) { if (text) Module.printErr('[post-exception status] ' + text); };
         };
     </script>
+    
+    <!-- NOTE: This code snippet displays a button that resumes blocked AudioContexts by 
+         the autoplay policy. For more detail on the autoplay change in Chrome, check:
+         https://developers.google.com/web/updates/2017/09/autoplay-policy-changes#webaudio. -->
+    <script type='text/javascript'>
+        /*
+        * Copyright 2018 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.
+        */
+        (function() {
+            const list = []; 
+            self.AudioContext = new Proxy(self.AudioContext, {
+                construct(target, args) {
+                    const result = new target(...args);
+                    list.push(result);
+                    return result;
+                }   
+            }); 
+
+            const btn = document.createElement('button');
+            
+            btn.classList.add('unmute');
+            btn.style.position = 'fixed';
+            btn.style.bottom = '0';
+            btn.style.right = '0';
+            btn.textContent = '🔇 Unmute';
+            btn.style.fontSize = '5em';
+            btn.onclick = e => {
+                list.forEach(ctx => ctx.resume());
+                btn.remove();
+            };
+            
+            document.addEventListener('DOMContentLoaded', _ => { document.body.appendChild(btn); }); 
+        })();
+    </script>
     {{{ SCRIPT }}}
   </body>
-</html>
+</html>