diff --git a/dom/quota/test/xpcshell/common/head.js b/dom/quota/test/xpcshell/common/head.js
index 57fb23349014..dc751868d532 100644
--- a/dom/quota/test/xpcshell/common/head.js
+++ b/dom/quota/test/xpcshell/common/head.js
@@ -11,16 +11,9 @@ const NS_ERROR_FILE_NO_DEVICE_SPACE = Cr.NS_ERROR_FILE_NO_DEVICE_SPACE;
 const loggingEnabled = false;
 
 var testGenerator;
-var childScriptPaths = [];
 
 loadScript("dom/quota/test/common/xpcshell.js");
 
-// Adds a test that will run in a child process (besides the main test that will
-// run in the main process).
-function loadChildScript(path) {
-  childScriptPaths.push(depth + path);
-}
-
 function log(msg) {
   if (loggingEnabled) {
     info(msg);
@@ -40,34 +33,15 @@ function todo(cond, msg) {
 }
 
 function run_test() {
-  let testHarnessGenerator;
+  runTest();
+}
 
-  function nextTestHarnessStep(val) {
-    testHarnessGenerator.next(val);
-  }
+if (!this.runTest) {
+  this.runTest = function() {
+    do_get_profile();
 
-  function* testHarnessSteps() {
-    do_test_pending("testHarnessSteps");
-
-    if (Services.appinfo.processType == Ci.nsIXULRuntime.PROCESS_TYPE_DEFAULT) {
-      do_get_profile();
-
-      enableStorageTesting();
-      enableTesting();
-
-      registerCleanupFunction(function() {
-        resetStorageTesting();
-        resetTesting();
-      });
-
-      if (childScriptPaths.length) {
-        // We currently allow defining multiple child tests by calling
-        // loadChildScript multiple times, but run_test_in_child supports
-        // loading of one test only.
-        run_test_in_child(childScriptPaths[0]).then(nextTestHarnessStep);
-        yield undefined;
-      }
-    }
+    enableStorageTesting();
+    enableTesting();
 
     Cu.importGlobalProperties(["indexedDB", "File", "Blob", "FileReader"]);
 
@@ -79,6 +53,13 @@ function run_test() {
       "There should be a testSteps function"
     );
     if (testSteps.constructor.name === "AsyncFunction") {
+      // Do run our existing cleanup function that would normally be called by
+      // the generator's call to finishTest().
+      registerCleanupFunction(function() {
+        resetStorageTesting();
+        resetTesting();
+      });
+
       add_task(testSteps);
 
       // Since we defined run_test, we must invoke run_next_test() to start the
@@ -90,22 +71,20 @@ function run_test() {
         "Unsupported function type"
       );
 
-      do_test_pending("testSteps");
+      do_test_pending();
 
       testGenerator = testSteps();
       testGenerator.next();
     }
-
-    do_test_finished("testHarnessSteps");
-  }
-
-  testHarnessGenerator = testHarnessSteps();
-  testHarnessGenerator.next();
+  };
 }
 
 function finishTest() {
+  resetStorageTesting();
+  resetTesting();
+
   executeSoon(function() {
-    do_test_finished("testSteps");
+    do_test_finished();
   });
 }
 
diff --git a/dom/quota/test/xpcshell/test_listOrigins.js b/dom/quota/test/xpcshell/test_listOrigins.js
index cf926f989357..9a683eedbbb2 100644
--- a/dom/quota/test/xpcshell/test_listOrigins.js
+++ b/dom/quota/test/xpcshell/test_listOrigins.js
@@ -3,8 +3,6 @@
  * http://creativecommons.org/publicdomain/zero/1.0/
  */
 
-loadChildScript("dom/quota/test/xpcshell/test_listOrigins.js");
-
 async function testSteps() {
   const origins = [
     "https://example.com",
diff --git a/dom/quota/test/xpcshell/test_originWithCaret.js b/dom/quota/test/xpcshell/test_originWithCaret.js
index 5ec53637a683..7afce4f5cccf 100644
--- a/dom/quota/test/xpcshell/test_originWithCaret.js
+++ b/dom/quota/test/xpcshell/test_originWithCaret.js
@@ -5,8 +5,6 @@
 
 "use strict";
 
-loadChildScript("dom/quota/test/xpcshell/test_originWithCaret.js");
-
 async function testSteps() {
   Assert.throws(
     () => {
diff --git a/dom/quota/test/xpcshell/test_simpledb.js b/dom/quota/test/xpcshell/test_simpledb.js
index a3f42aa7d927..b698d778e090 100644
--- a/dom/quota/test/xpcshell/test_simpledb.js
+++ b/dom/quota/test/xpcshell/test_simpledb.js
@@ -3,7 +3,4 @@
  * http://creativecommons.org/publicdomain/zero/1.0/
  */
 
-const commonScriptPath = "dom/quota/test/common/test_simpledb.js";
-
-loadScript(commonScriptPath);
-loadChildScript(commonScriptPath);
+loadScript("dom/quota/test/common/test_simpledb.js");