diff --git a/js/src/xpconnect/shell/xpcshell.cpp b/js/src/xpconnect/shell/xpcshell.cpp
index 4ec95ce0ef9..aba7d758e4c 100644
--- a/js/src/xpconnect/shell/xpcshell.cpp
+++ b/js/src/xpconnect/shell/xpcshell.cpp
@@ -1141,7 +1141,7 @@ static int
 usage(void)
 {
     fprintf(gErrFile, "%s\n", JS_GetImplementationVersion());
-    fprintf(gErrFile, "usage: xpcshell [-g gredir] [-PsSwWxCij] [-v version] [-f scriptfile] [-e script] [scriptfile] [scriptarg...]\n");
+    fprintf(gErrFile, "usage: xpcshell [-g gredir] [-r manifest]... [-PsSwWxCij] [-v version] [-f scriptfile] [-e script] [scriptfile] [scriptarg...]\n");
     return 2;
 }
 
@@ -1819,6 +1819,22 @@ main(int argc, char **argv)
         argv += 2;
     }
 
+    while (argc > 1 && !strcmp(argv[1], "-r")) {
+        if (argc < 3)
+            return usage();
+
+        nsCOMPtr<nsILocalFile> lf;
+        rv = XRE_GetFileFromPath(argv[2], getter_AddRefs(lf));
+        if (NS_FAILED(rv)) {
+            printf("Couldn't get manifest file.\n");
+            return 1;
+        }
+        XRE_AddManifestLocation(NS_COMPONENT_LOCATION, lf);
+
+        argc -= 2;
+        argv += 2;
+    }
+
     {
         nsCOMPtr<nsIServiceManager> servMan;
         rv = NS_InitXPCOM2(getter_AddRefs(servMan), appDir, &dirprovider);
diff --git a/testing/xpcshell/runxpcshelltests.py b/testing/xpcshell/runxpcshelltests.py
index 94646a9cb7f..0de66b7f3a8 100644
--- a/testing/xpcshell/runxpcshelltests.py
+++ b/testing/xpcshell/runxpcshelltests.py
@@ -139,6 +139,9 @@ class XPCShellTests(object):
     self.httpdJSPath = os.path.join(os.path.dirname(self.xpcshell), 'components', 'httpd.js')
     self.httpdJSPath = replaceBackSlashes(self.httpdJSPath)
 
+    self.httpdManifest = os.path.join(os.path.dirname(self.xpcshell), 'components', 'httpd.manifest')
+    self.httpdManifest = replaceBackSlashes(self.httpdManifest)
+
     if self.xrePath is None:
       self.xrePath = os.path.dirname(self.xpcshell)
     else:
@@ -204,7 +207,7 @@ class XPCShellTests(object):
     """
     # - NOTE: if you rename/add any of the constants set here, update
     #   do_load_child_test_harness() in head.js
-    self.xpcsCmd = [self.xpcshell, '-g', self.xrePath, '-j', '-s'] + \
+    self.xpcsCmd = [self.xpcshell, '-g', self.xrePath, '-r', self.httpdManifest, '-j', '-s'] + \
         ['-e', 'const _HTTPD_JS_PATH = "%s";' % self.httpdJSPath,
          '-e', 'const _HEAD_JS_PATH = "%s";' % self.headJSPath,
          '-f', os.path.join(self.testharnessdir, 'head.js')]