Bug 815299 - Part 2: Accept empty HTTP headers in fetch; r=jdm

dom/fetch/FetchDriver.cpp

@@ -477,7 +477,11 @@ FetchDriver::HttpFetch(bool aCORSFlag, bool aCORSPreflightFlag, bool aAuthentica
     nsAutoTArray<InternalHeaders::Entry, 5> headers;
     mRequest->Headers()->GetEntries(headers);
     for (uint32_t i = 0; i < headers.Length(); ++i) {
-      httpChan->SetRequestHeader(headers[i].mName, headers[i].mValue, false /* merge */);
+      if (headers[i].mValue.IsEmpty()) {
+        httpChan->SetEmptyRequestHeader(headers[i].mName);
+      } else {
+        httpChan->SetRequestHeader(headers[i].mName, headers[i].mValue, false /* merge */);
+      }
     }
 
     // Step 2. Set the referrer.

dom/workers/test/serviceworkers/fetch/fetch_tests.js

@@ -320,3 +320,12 @@ fetch(new Request('body-blob', {method: 'POST', body: new Blob(new String('my bo
     finish();
   });
 });
+
+expectAsyncResult();
+fetch(new Request('empty-header', {headers:{"emptyheader":""}}))
+.then(function(res) {
+  return res.text();
+}).then(function(body) {
+  my_ok(body == "emptyheader", "The empty header was observed in the fetch event");
+  finish();
+});

dom/workers/test/serviceworkers/fetch_event_worker.js

@@ -274,4 +274,13 @@ onfetch = function(ev) {
   else if (ev.request.url.includes('xhr-method-test.txt')) {
     ev.respondWith(new Response('intercepted ' + ev.request.method));
   }
+
+  else if (ev.request.url.includes('empty-header')) {
+    if (!ev.request.headers.has("emptyheader") ||
+        ev.request.headers.get("emptyheader") !== "") {
+      ev.respondWith(Promise.reject());
+      return;
+    }
+    ev.respondWith(new Response("emptyheader"));
+  }
 };