--- a/testing/specialpowers/content/SpecialPowersObserverAPI.js
+++ b/testing/specialpowers/content/SpecialPowersObserverAPI.js
@@ -6,16 +6,17 @@
 
 ChromeUtils.import("resource://gre/modules/XPCOMUtils.jsm");
 
 XPCOMUtils.defineLazyModuleGetters(this, {
   ExtensionData: "resource://gre/modules/Extension.jsm",
   ExtensionTestCommon: "resource://testing-common/ExtensionTestCommon.jsm",
   NetUtil: "resource://gre/modules/NetUtil.jsm",
   Services: "resource://gre/modules/Services.jsm",
+  PerTestCoverageUtils: "resource://testing-common/PerTestCoverageUtils.jsm",
 });
 
 this.SpecialPowersError = function(aMsg) {
   Error.call(this);
   // let {stack} = new Error();
   this.message = aMsg;
   this.name = "SpecialPowersError";
 };
@@ -549,26 +550,26 @@ SpecialPowersObserverAPI.prototype = {
         let uri = Services.io.newURI(origin);
         let sss = Cc["@mozilla.org/ssservice;1"].
                   getService(Ci.nsISiteSecurityService);
         sss.removeState(Ci.nsISiteSecurityService.HEADER_HSTS, uri, flags);
         return undefined;
       }
 
       case "SPRequestDumpCoverageCounters": {
-        let codeCoverage = Cc["@mozilla.org/tools/code-coverage;1"].
-                           getService(Ci.nsICodeCoverage);
-        codeCoverage.dumpCounters();
+        PerTestCoverageUtils.afterTest().then(() =>
+          this._sendReply(aMessage, "SPRequestDumpCoverageCounters", {})
+        );
         return undefined; // See comment at the beginning of this function.
       }
 
       case "SPRequestResetCoverageCounters": {
-        let codeCoverage = Cc["@mozilla.org/tools/code-coverage;1"].
-                           getService(Ci.nsICodeCoverage);
-        codeCoverage.resetCounters();
+        PerTestCoverageUtils.beforeTest().then(() =>
+          this._sendReply(aMessage, "SPRequestResetCoverageCounters", {})
+        );
         return undefined; // See comment at the beginning of this function.
       }
 
       case "SPLoadExtension": {
         let id = aMessage.data.id;
         let ext = aMessage.data.ext;
         let extension = ExtensionTestCommon.generate(ext);
 

--- a/testing/specialpowers/content/specialpowers.js
+++ b/testing/specialpowers/content/specialpowers.js
@@ -30,30 +30,30 @@ function SpecialPowers(window) {
   this.SP_SYNC_MESSAGES = ["SPChromeScriptMessage",
                            "SPLoadChromeScript",
                            "SPImportInMainProcess",
                            "SPObserverService",
                            "SPPermissionManager",
                            "SPPrefService",
                            "SPProcessCrashService",
                            "SPSetTestPluginEnabledState",
-                           "SPCleanUpSTSData",
-                           "SPRequestDumpCoverageCounters",
-                           "SPRequestResetCoverageCounters"];
+                           "SPCleanUpSTSData"];
 
   this.SP_ASYNC_MESSAGES = ["SpecialPowers.Focus",
                             "SpecialPowers.Quit",
                             "SpecialPowers.CreateFiles",
                             "SpecialPowers.RemoveFiles",
                             "SPPingService",
                             "SPLoadExtension",
                             "SPProcessCrashManagerWait",
                             "SPStartupExtension",
                             "SPUnloadExtension",
-                            "SPExtensionMessage"];
+                            "SPExtensionMessage",
+                            "SPRequestDumpCoverageCounters",
+                            "SPRequestResetCoverageCounters"];
   addMessageListener("SPPingService", this._messageListener);
   addMessageListener("SpecialPowers.FilesCreated", this._messageListener);
   addMessageListener("SpecialPowers.FilesError", this._messageListener);
   let self = this;
   Services.obs.addObserver(function onInnerWindowDestroyed(subject, topic, data) {
     var id = subject.QueryInterface(Ci.nsISupportsPRUint64).data;
     if (self._windowID === id) {
       Services.obs.removeObserver(onInnerWindowDestroyed, "inner-window-destroyed");

--- a/testing/specialpowers/content/specialpowersAPI.js
+++ b/testing/specialpowers/content/specialpowersAPI.js
@@ -1977,22 +1977,34 @@ SpecialPowersAPI.prototype = {
   removeServiceWorkerDataForExampleDomain() {
     return wrapIfUnwrapped(ServiceWorkerCleanUp.removeFromHost("example.com"));
   },
 
   cleanUpSTSData(origin, flags) {
     return this._sendSyncMessage("SPCleanUpSTSData", {origin, flags: flags || 0});
   },
 
-  requestDumpCoverageCounters() {
-    this._sendSyncMessage("SPRequestDumpCoverageCounters", {});
+  requestDumpCoverageCounters(cb) {
+    let messageListener = _ => {
+      this._removeMessageListener("SPRequestDumpCoverageCounters", messageListener);
+      cb();
+    };
+
+    this._addMessageListener("SPRequestDumpCoverageCounters", messageListener);
+    this._sendAsyncMessage("SPRequestDumpCoverageCounters", {});
   },
 
-  requestResetCoverageCounters() {
-    this._sendSyncMessage("SPRequestResetCoverageCounters", {});
+  requestResetCoverageCounters(cb) {
+    let messageListener = _ => {
+      this._removeMessageListener("SPRequestResetCoverageCounters", messageListener);
+      cb();
+    };
+
+    this._addMessageListener("SPRequestResetCoverageCounters", messageListener);
+    this._sendAsyncMessage("SPRequestResetCoverageCounters", {});
   },
 
   _nextExtensionID: 0,
   _extensionListeners: null,
 
   loadExtension(ext, handler) {
     if (this._extensionListeners == null) {
       this._extensionListeners = new Set();

--- a/tools/code-coverage/tests/mochitest/test_coverage_specialpowers.html
+++ b/tools/code-coverage/tests/mochitest/test_coverage_specialpowers.html
@@ -9,23 +9,25 @@ https://bugzilla.mozilla.org/show_bug.cg
   <script type="application/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
   <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
   <script type="application/javascript">
 
   /** Test for Bug 1380659 **/
 
   SimpleTest.waitForExplicitFinish();
 
-  SpecialPowers.requestDumpCoverageCounters();
-  SimpleTest.ok(true, "Counters dumped.");
+  (async function() {
+    await new Promise(resolve => SpecialPowers.requestDumpCoverageCounters(resolve));
+    SimpleTest.ok(true, "Counters dumped.");
 
-  SpecialPowers.requestResetCoverageCounters();
-  SimpleTest.ok(true, "Counters reset.");
+    await new Promise(resolve => SpecialPowers.requestResetCoverageCounters(resolve));
+    SimpleTest.ok(true, "Counters reset.");
 
-  SimpleTest.finish();
+    SimpleTest.finish();
+  })();
 
   </script>
 </head>
 <body>
 <a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1380659">Mozilla Bug 1380659</a>
 <p id="display"></p>
 <div id="content" style="display: none">