Bug 1217501 P3 Check Accept header visibility in service worker fetch event. r=ehsan

testing/web-platform/mozilla/tests/service-workers/service-worker/fetch-header-visibility.https.html

@@ -23,7 +23,7 @@
 
         // Resolve a promise when we recieve 2 success messages
         return new Promise(function(resolve, reject) {
-          var remaining = 2;
+          var remaining = 4;
           function onMessage(e) {
             if (e.data == 'PASS') {
               remaining--;

testing/web-platform/mozilla/tests/service-workers/service-worker/resources/fetch-header-visibility-iframe.html

@@ -32,4 +32,35 @@
   }).catch(function(err) {
     parent.postMessage('noUA FAIL - unexpected error: ' + err, '*');
   });
+
+  var uri = document.location + '?check-accept-header';
+  var headers = new Headers();
+  headers.set('Accept', 'hmm');
+
+  // Check for custom accept header
+  fetch(uri, { headers: headers }).then(function(response) {
+    return response.text();
+  }).then(function(text) {
+    if (text === headers.get('Accept')) {
+      parent.postMessage('PASS', '*');
+    } else {
+      parent.postMessage('custom accept FAIL - expected ' + headers.get('Accept') +
+                         ' got "' + text + '"', '*');
+    }
+  }).catch(function(err) {
+    parent.postMessage('custom accept FAIL - unexpected error: ' + err, '*');
+  });
+
+  // Check for default accept header
+  fetch(uri).then(function(response) {
+    return response.text();
+  }).then(function(text) {
+    if (text === '*/*') {
+      parent.postMessage('PASS', '*');
+    } else {
+      parent.postMessage('accept FAIL - expected */* got "' + text + '"', '*');
+    }
+  }).catch(function(err) {
+    parent.postMessage('accept FAIL - unexpected error: ' + err, '*');
+  });
 </script>

testing/web-platform/mozilla/tests/service-workers/service-worker/resources/fetch-rewrite-worker.js

@@ -63,6 +63,14 @@ self.addEventListener('fetch', function(event) {
       }
       return;
     }
+    if (params['check-accept-header']) {
+      var accept = event.request.headers.get('Accept');
+      if (accept) {
+        event.respondWith(new Response(accept));
+      } else {
+        event.respondWith(new Response('NO_ACCEPT'));
+      }
+    }
     event.respondWith(new Promise(function(resolve, reject) {
         var request = event.request;
         if (url) {