diff --git a/netwerk/protocol/http/HttpChannelChild.cpp b/netwerk/protocol/http/HttpChannelChild.cpp
index 9dceeb4745a2..7efd6bf03c4e 100644
--- a/netwerk/protocol/http/HttpChannelChild.cpp
+++ b/netwerk/protocol/http/HttpChannelChild.cpp
@@ -3721,7 +3721,10 @@ nsresult HttpChannelChild::AsyncCallImpl(
 }
 
 nsresult HttpChannelChild::SetReferrerHeader(const nsACString& aReferrer) {
-  ENSURE_CALLED_BEFORE_CONNECT();
+  // Normally this would be ENSURE_CALLED_BEFORE_CONNECT, but since the
+  // "connect" is done in the main process, and mRequestObserversCalled is never
+  // set in the ChannelChild, before connect basically means before asyncOpen.
+  ENSURE_CALLED_BEFORE_ASYNC_OPEN();
 
   // remove old referrer if any, loop backwards
   for (int i = mClientSetRequestHeaders.Length() - 1; i >= 0; --i) {
diff --git a/netwerk/test/unit/test_httpcancel.js b/netwerk/test/unit/test_httpcancel.js
index 9cface8225f9..587faf18cfbb 100644
--- a/netwerk/test/unit/test_httpcancel.js
+++ b/netwerk/test/unit/test_httpcancel.js
@@ -6,6 +6,12 @@
 
 const {HttpServer} = ChromeUtils.import("resource://testing-common/httpd.js");
 
+function inChildProcess() {
+  return Cc["@mozilla.org/xre/app-info;1"]
+           .getService(Ci.nsIXULRuntime)
+           .processType != Ci.nsIXULRuntime.PROCESS_TYPE_DEFAULT;
+}
+
 var ios = Cc["@mozilla.org/network/io-service;1"]
             .getService(Ci.nsIIOService);
 var ReferrerInfo = Components.Constructor("@mozilla.org/referrer-info;1",
@@ -90,9 +96,11 @@ function execute_test() {
   var chan = makeChan("http://localhost:" +
                       httpserv.identity.primaryPort + "/failtest");
 
-  var obs = Cc["@mozilla.org/observer-service;1"].getService();
-  obs = obs.QueryInterface(Ci.nsIObserverService);
-  obs.addObserver(observer, "http-on-modify-request");
+  if (!inChildProcess()) {
+    var obs = Cc["@mozilla.org/observer-service;1"].getService();
+    obs = obs.QueryInterface(Ci.nsIObserverService);
+    obs.addObserver(observer, "http-on-modify-request");
+  }
 
   chan.asyncOpen(listener);
 }
diff --git a/netwerk/test/unit_ipc/test_httpcancel_wrap.js b/netwerk/test/unit_ipc/test_httpcancel_wrap.js
new file mode 100644
index 000000000000..469e748266e8
--- /dev/null
+++ b/netwerk/test/unit_ipc/test_httpcancel_wrap.js
@@ -0,0 +1,46 @@
+"use strict";
+
+const {HttpServer} = ChromeUtils.import("resource://testing-common/httpd.js");
+const {Services} = ChromeUtils.import("resource://gre/modules/Services.jsm");
+
+const ReferrerInfo = Components.Constructor("@mozilla.org/referrer-info;1",
+                                            "nsIReferrerInfo",
+                                            "init");
+
+let observer = {
+  QueryInterface: function eventsink_qi(iid) {
+    if (iid.equals(Ci.nsISupports) ||
+        iid.equals(Ci.nsIObserver))
+      return this;
+    throw Cr.NS_ERROR_NO_INTERFACE;
+  },
+
+  observe: function(subject, topic, data) {
+    subject = subject.QueryInterface(Ci.nsIRequest);
+    subject.cancel(Cr.NS_BINDING_ABORTED);
+
+    // ENSURE_CALLED_BEFORE_CONNECT: setting values should still work
+    try {
+      subject.QueryInterface(Ci.nsIHttpChannel);
+      let currentReferrer = subject.getRequestHeader("Referer");
+      Assert.equal(currentReferrer, "http://site1.com/");
+      let uri = Services.io.newURI("http://site2.com");
+      subject.referrerInfo = new ReferrerInfo(Ci.nsIHttpChannel.REFERRER_POLICY_UNSET, true, uri);
+    } catch (ex) {
+      do_throw("Exception: " + ex);
+    }
+
+    let obs = Cc["@mozilla.org/observer-service;1"].getService();
+    obs = obs.QueryInterface(Ci.nsIObserverService);
+    obs.removeObserver(observer, "http-on-modify-request");
+  }
+};
+
+function run_test() {
+
+  let obs = Cc["@mozilla.org/observer-service;1"].getService();
+  obs = obs.QueryInterface(Ci.nsIObserverService);
+  obs.addObserver(observer, "http-on-modify-request");
+
+  run_test_in_child("../unit/test_httpcancel.js");
+}
diff --git a/netwerk/test/unit_ipc/xpcshell.ini b/netwerk/test/unit_ipc/xpcshell.ini
index 26ada9b70042..12aee430a8b8 100644
--- a/netwerk/test/unit_ipc/xpcshell.ini
+++ b/netwerk/test/unit_ipc/xpcshell.ini
@@ -58,6 +58,7 @@ support-files =
   !/netwerk/test/unit/test_multipart_streamconv.js
   !/netwerk/test/unit/test_original_sent_received_head.js
   !/netwerk/test/unit/test_alt-data_cross_process.js
+  !/netwerk/test/unit/test_httpcancel.js
   child_cookie_header.js
 
 [test_bug528292_wrap.js]
@@ -106,3 +107,4 @@ skip-if = true
 [test_channel_priority_wrap.js]
 [test_multipart_streamconv_wrap.js]
 [test_alt-data_cross_process_wrap.js]
+[test_httpcancel_wrap.js]