diff --git a/browser/devtools/webaudioeditor/test/browser_audionode-actor-get-param-flags.js b/browser/devtools/webaudioeditor/test/browser_audionode-actor-get-param-flags.js
index a71e6d2a2c6..e12368291e2 100644
--- a/browser/devtools/webaudioeditor/test/browser_audionode-actor-get-param-flags.js
+++ b/browser/devtools/webaudioeditor/test/browser_audionode-actor-get-param-flags.js
@@ -6,7 +6,7 @@
  */
 
 function spawnTest () {
-  let { target, front } = yield initBackend(SIMPLE_NODES_URL);
+  let [target, debuggee, front] = yield initBackend(SIMPLE_NODES_URL);
   let [_, nodes] = yield Promise.all([
     front.setup({ reload: true }),
     getN(front, "create-node", 14)
diff --git a/browser/devtools/webaudioeditor/test/browser_audionode-actor-get-params-01.js b/browser/devtools/webaudioeditor/test/browser_audionode-actor-get-params-01.js
index 9c88ff0b54f..046dffa6f8a 100644
--- a/browser/devtools/webaudioeditor/test/browser_audionode-actor-get-params-01.js
+++ b/browser/devtools/webaudioeditor/test/browser_audionode-actor-get-params-01.js
@@ -6,7 +6,7 @@
  */
 
 function spawnTest () {
-  let { target, front } = yield initBackend(SIMPLE_NODES_URL);
+  let [target, debuggee, front] = yield initBackend(SIMPLE_NODES_URL);
   let [_, nodes] = yield Promise.all([
     front.setup({ reload: true }),
     getN(front, "create-node", 14)
diff --git a/browser/devtools/webaudioeditor/test/browser_audionode-actor-get-params-02.js b/browser/devtools/webaudioeditor/test/browser_audionode-actor-get-params-02.js
index c426cab925e..7a7bb95bca6 100644
--- a/browser/devtools/webaudioeditor/test/browser_audionode-actor-get-params-02.js
+++ b/browser/devtools/webaudioeditor/test/browser_audionode-actor-get-params-02.js
@@ -7,7 +7,7 @@
  */
 
 function spawnTest() {
-  let { target, front } = yield initBackend(SIMPLE_NODES_URL);
+  let [target, debuggee, front] = yield initBackend(SIMPLE_NODES_URL);
   let [_, nodes] = yield Promise.all([
     front.setup({ reload: true }),
     getN(front, "create-node", 14)
diff --git a/browser/devtools/webaudioeditor/test/browser_audionode-actor-get-set-param.js b/browser/devtools/webaudioeditor/test/browser_audionode-actor-get-set-param.js
index da6de234e2e..da17619edb6 100644
--- a/browser/devtools/webaudioeditor/test/browser_audionode-actor-get-set-param.js
+++ b/browser/devtools/webaudioeditor/test/browser_audionode-actor-get-set-param.js
@@ -6,7 +6,7 @@
  */
 
 function spawnTest () {
-  let { target, front } = yield initBackend(SIMPLE_CONTEXT_URL);
+  let [target, debuggee, front] = yield initBackend(SIMPLE_CONTEXT_URL);
   let [_, [destNode, oscNode, gainNode]] = yield Promise.all([
     front.setup({ reload: true }),
     get3(front, "create-node")
diff --git a/browser/devtools/webaudioeditor/test/browser_audionode-actor-get-type.js b/browser/devtools/webaudioeditor/test/browser_audionode-actor-get-type.js
index b4ec5e5f6b9..c4ac400d95b 100644
--- a/browser/devtools/webaudioeditor/test/browser_audionode-actor-get-type.js
+++ b/browser/devtools/webaudioeditor/test/browser_audionode-actor-get-type.js
@@ -6,7 +6,7 @@
  */
 
 function spawnTest () {
-  let { target, front } = yield initBackend(SIMPLE_NODES_URL);
+  let [target, debuggee, front] = yield initBackend(SIMPLE_NODES_URL);
   let [_, nodes] = yield Promise.all([
     front.setup({ reload: true }),
     getN(front, "create-node", 14)
diff --git a/browser/devtools/webaudioeditor/test/browser_audionode-actor-is-source.js b/browser/devtools/webaudioeditor/test/browser_audionode-actor-is-source.js
index bc99540ef9b..942edde7f4d 100644
--- a/browser/devtools/webaudioeditor/test/browser_audionode-actor-is-source.js
+++ b/browser/devtools/webaudioeditor/test/browser_audionode-actor-is-source.js
@@ -6,7 +6,7 @@
  */
 
 function spawnTest () {
-  let { target, front } = yield initBackend(SIMPLE_NODES_URL);
+  let [target, debuggee, front] = yield initBackend(SIMPLE_NODES_URL);
   let [_, nodes] = yield Promise.all([
     front.setup({ reload: true }),
     getN(front, "create-node", 14)
diff --git a/browser/devtools/webaudioeditor/test/browser_wa_destroy-node-01.js b/browser/devtools/webaudioeditor/test/browser_wa_destroy-node-01.js
index d8b27e945e9..d3f14a2b96b 100644
--- a/browser/devtools/webaudioeditor/test/browser_wa_destroy-node-01.js
+++ b/browser/devtools/webaudioeditor/test/browser_wa_destroy-node-01.js
@@ -10,7 +10,7 @@
  */
 
 function spawnTest() {
-  let { target, panel } = yield initWebAudioEditor(DESTROY_NODES_URL);
+  let [target, debuggee, panel] = yield initWebAudioEditor(DESTROY_NODES_URL);
   let { panelWin } = panel;
   let { gFront, $, $$, gAudioNodes } = panelWin;
 
diff --git a/browser/devtools/webaudioeditor/test/browser_wa_first-run.js b/browser/devtools/webaudioeditor/test/browser_wa_first-run.js
index 7b377a5d0ba..5fc4a27ca28 100644
--- a/browser/devtools/webaudioeditor/test/browser_wa_first-run.js
+++ b/browser/devtools/webaudioeditor/test/browser_wa_first-run.js
@@ -6,7 +6,7 @@
  */
 
 function spawnTest() {
-  let { target, panel } = yield initWebAudioEditor(SIMPLE_CONTEXT_URL);
+  let [target, debuggee, panel] = yield initWebAudioEditor(SIMPLE_CONTEXT_URL);
   let { gFront, $ } = panel.panelWin;
 
   is($("#reload-notice").hidden, false,
diff --git a/browser/devtools/webaudioeditor/test/browser_wa_graph-click.js b/browser/devtools/webaudioeditor/test/browser_wa_graph-click.js
index 822c5dd2447..d6b307194a0 100644
--- a/browser/devtools/webaudioeditor/test/browser_wa_graph-click.js
+++ b/browser/devtools/webaudioeditor/test/browser_wa_graph-click.js
@@ -7,7 +7,7 @@
  */
 
 function spawnTest() {
-  let { target, panel } = yield initWebAudioEditor(COMPLEX_CONTEXT_URL);
+  let [target, debuggee, panel] = yield initWebAudioEditor(COMPLEX_CONTEXT_URL);
   let panelWin = panel.panelWin;
   let { gFront, $, $$, InspectorView } = panelWin;
 
diff --git a/browser/devtools/webaudioeditor/test/browser_wa_graph-markers.js b/browser/devtools/webaudioeditor/test/browser_wa_graph-markers.js
index d1264043e97..5961837e275 100644
--- a/browser/devtools/webaudioeditor/test/browser_wa_graph-markers.js
+++ b/browser/devtools/webaudioeditor/test/browser_wa_graph-markers.js
@@ -6,7 +6,7 @@
  */
 
 function spawnTest() {
-  let { target, panel } = yield initWebAudioEditor(SIMPLE_CONTEXT_URL);
+  let [target, debuggee, panel] = yield initWebAudioEditor(SIMPLE_CONTEXT_URL);
   let { panelWin } = panel;
   let { gFront, $, $$, MARKER_STYLING } = panelWin;
 
diff --git a/browser/devtools/webaudioeditor/test/browser_wa_graph-render-01.js b/browser/devtools/webaudioeditor/test/browser_wa_graph-render-01.js
index 290022b1e91..b036cc1741f 100644
--- a/browser/devtools/webaudioeditor/test/browser_wa_graph-render-01.js
+++ b/browser/devtools/webaudioeditor/test/browser_wa_graph-render-01.js
@@ -8,7 +8,7 @@
 let connectCount = 0;
 
 function spawnTest() {
-  let { target, panel } = yield initWebAudioEditor(SIMPLE_CONTEXT_URL);
+  let [target, debuggee, panel] = yield initWebAudioEditor(SIMPLE_CONTEXT_URL);
   let { panelWin } = panel;
   let { gFront, $, $$, EVENTS, gAudioNodes } = panelWin;
 
diff --git a/browser/devtools/webaudioeditor/test/browser_wa_graph-render-02.js b/browser/devtools/webaudioeditor/test/browser_wa_graph-render-02.js
index a52f63fd874..aa3b18d2e81 100644
--- a/browser/devtools/webaudioeditor/test/browser_wa_graph-render-02.js
+++ b/browser/devtools/webaudioeditor/test/browser_wa_graph-render-02.js
@@ -6,7 +6,7 @@
  */
 
 function spawnTest() {
-  let { target, panel } = yield initWebAudioEditor(COMPLEX_CONTEXT_URL);
+  let [target, debuggee, panel] = yield initWebAudioEditor(COMPLEX_CONTEXT_URL);
   let { panelWin } = panel;
   let { gFront, $, $$ } = panelWin;
 
diff --git a/browser/devtools/webaudioeditor/test/browser_wa_graph-render-03.js b/browser/devtools/webaudioeditor/test/browser_wa_graph-render-03.js
index 6ec4cea209f..784d7fe47f7 100644
--- a/browser/devtools/webaudioeditor/test/browser_wa_graph-render-03.js
+++ b/browser/devtools/webaudioeditor/test/browser_wa_graph-render-03.js
@@ -6,7 +6,7 @@
  */
 
 function spawnTest() {
-  let { target, panel } = yield initWebAudioEditor(CONNECT_TOGGLE_URL);
+  let [target, debuggee, panel] = yield initWebAudioEditor(CONNECT_TOGGLE_URL);
   let { panelWin } = panel;
   let { gFront, $, $$, EVENTS } = panelWin;
 
diff --git a/browser/devtools/webaudioeditor/test/browser_wa_graph-render-04.js b/browser/devtools/webaudioeditor/test/browser_wa_graph-render-04.js
index 1292b84851e..493a9baf63e 100644
--- a/browser/devtools/webaudioeditor/test/browser_wa_graph-render-04.js
+++ b/browser/devtools/webaudioeditor/test/browser_wa_graph-render-04.js
@@ -6,7 +6,7 @@
  */
 
 function spawnTest() {
-  let { target, panel } = yield initWebAudioEditor(CONNECT_MULTI_PARAM_URL);
+  let [target, debuggee, panel] = yield initWebAudioEditor(CONNECT_MULTI_PARAM_URL);
   let { panelWin } = panel;
   let { gFront, $, $$, EVENTS } = panelWin;
 
diff --git a/browser/devtools/webaudioeditor/test/browser_wa_graph-selected.js b/browser/devtools/webaudioeditor/test/browser_wa_graph-selected.js
index 51edb953182..bd667d7523d 100644
--- a/browser/devtools/webaudioeditor/test/browser_wa_graph-selected.js
+++ b/browser/devtools/webaudioeditor/test/browser_wa_graph-selected.js
@@ -6,7 +6,7 @@
  */
 
 function spawnTest() {
-  let { target, panel } = yield initWebAudioEditor(SIMPLE_CONTEXT_URL);
+  let [target, debuggee, panel] = yield initWebAudioEditor(SIMPLE_CONTEXT_URL);
   let { panelWin } = panel;
   let { gFront, $, $$, EVENTS } = panelWin;
 
diff --git a/browser/devtools/webaudioeditor/test/browser_wa_graph-zoom.js b/browser/devtools/webaudioeditor/test/browser_wa_graph-zoom.js
index 0ec876a783f..f90b2499195 100644
--- a/browser/devtools/webaudioeditor/test/browser_wa_graph-zoom.js
+++ b/browser/devtools/webaudioeditor/test/browser_wa_graph-zoom.js
@@ -6,7 +6,7 @@
  */
 
 function spawnTest() {
-  let { target, panel } = yield initWebAudioEditor(SIMPLE_CONTEXT_URL);
+  let [target, debuggee, panel] = yield initWebAudioEditor(SIMPLE_CONTEXT_URL);
   let { panelWin } = panel;
   let { gFront, $, $$, EVENTS, ContextView } = panelWin;
 
diff --git a/browser/devtools/webaudioeditor/test/browser_wa_inspector-toggle.js b/browser/devtools/webaudioeditor/test/browser_wa_inspector-toggle.js
index d133e00d913..ed168960bfd 100644
--- a/browser/devtools/webaudioeditor/test/browser_wa_inspector-toggle.js
+++ b/browser/devtools/webaudioeditor/test/browser_wa_inspector-toggle.js
@@ -7,7 +7,7 @@
  */
 
 function spawnTest() {
-  let { target, panel } = yield initWebAudioEditor(SIMPLE_CONTEXT_URL);
+  let [target, debuggee, panel] = yield initWebAudioEditor(SIMPLE_CONTEXT_URL);
   let { panelWin } = panel;
   let { gFront, $, $$, EVENTS, InspectorView } = panelWin;
   let gVars = InspectorView._propsView;
diff --git a/browser/devtools/webaudioeditor/test/browser_wa_inspector.js b/browser/devtools/webaudioeditor/test/browser_wa_inspector.js
index 085d1751368..ff13dfbf87d 100644
--- a/browser/devtools/webaudioeditor/test/browser_wa_inspector.js
+++ b/browser/devtools/webaudioeditor/test/browser_wa_inspector.js
@@ -7,7 +7,7 @@
  */
 
 function spawnTest() {
-  let { target, panel } = yield initWebAudioEditor(SIMPLE_CONTEXT_URL);
+  let [target, debuggee, panel] = yield initWebAudioEditor(SIMPLE_CONTEXT_URL);
   let { panelWin } = panel;
   let { gFront, $, $$, EVENTS, InspectorView } = panelWin;
   let gVars = InspectorView._propsView;
diff --git a/browser/devtools/webaudioeditor/test/browser_wa_navigate.js b/browser/devtools/webaudioeditor/test/browser_wa_navigate.js
index a57c5ec725d..8bacd64eb59 100644
--- a/browser/devtools/webaudioeditor/test/browser_wa_navigate.js
+++ b/browser/devtools/webaudioeditor/test/browser_wa_navigate.js
@@ -7,7 +7,7 @@
  */
 
 function spawnTest() {
-  let { target, panel } = yield initWebAudioEditor(SIMPLE_CONTEXT_URL);
+  let [target, debuggee, panel] = yield initWebAudioEditor(SIMPLE_CONTEXT_URL);
   let { panelWin } = panel;
   let { gFront, $ } = panelWin;
 
diff --git a/browser/devtools/webaudioeditor/test/browser_wa_properties-view-edit-01.js b/browser/devtools/webaudioeditor/test/browser_wa_properties-view-edit-01.js
index 9b0495dfcc3..4e61b1645a5 100644
--- a/browser/devtools/webaudioeditor/test/browser_wa_properties-view-edit-01.js
+++ b/browser/devtools/webaudioeditor/test/browser_wa_properties-view-edit-01.js
@@ -6,7 +6,7 @@
  */
 
 function spawnTest() {
-  let { target, panel } = yield initWebAudioEditor(SIMPLE_CONTEXT_URL);
+  let [target, debuggee, panel] = yield initWebAudioEditor(SIMPLE_CONTEXT_URL);
   let { panelWin } = panel;
   let { gFront, $, $$, EVENTS, InspectorView } = panelWin;
   let gVars = InspectorView._propsView;
diff --git a/browser/devtools/webaudioeditor/test/browser_wa_properties-view-edit-02.js b/browser/devtools/webaudioeditor/test/browser_wa_properties-view-edit-02.js
index 322ae56542e..dc9b5fae23b 100644
--- a/browser/devtools/webaudioeditor/test/browser_wa_properties-view-edit-02.js
+++ b/browser/devtools/webaudioeditor/test/browser_wa_properties-view-edit-02.js
@@ -6,7 +6,7 @@
  */
 
 function spawnTest() {
-  let { target, panel } = yield initWebAudioEditor(COMPLEX_CONTEXT_URL);
+  let [target, debuggee, panel] = yield initWebAudioEditor(COMPLEX_CONTEXT_URL);
   let { panelWin } = panel;
   let { gFront, $, $$, EVENTS, InspectorView } = panelWin;
   let gVars = InspectorView._propsView;
diff --git a/browser/devtools/webaudioeditor/test/browser_wa_properties-view-media-nodes.js b/browser/devtools/webaudioeditor/test/browser_wa_properties-view-media-nodes.js
index f647e5b0b3d..7cf0b3b3a98 100644
--- a/browser/devtools/webaudioeditor/test/browser_wa_properties-view-media-nodes.js
+++ b/browser/devtools/webaudioeditor/test/browser_wa_properties-view-media-nodes.js
@@ -35,7 +35,7 @@ function waitForDeviceClosed() {
 }
 
 function spawnTest() {
-  let { target, panel } = yield initWebAudioEditor(MEDIA_NODES_URL);
+  let [target, debuggee, panel] = yield initWebAudioEditor(MEDIA_NODES_URL);
   let { panelWin } = panel;
   let { gFront, $, $$, EVENTS, InspectorView } = panelWin;
   let gVars = InspectorView._propsView;
diff --git a/browser/devtools/webaudioeditor/test/browser_wa_properties-view-params-objects.js b/browser/devtools/webaudioeditor/test/browser_wa_properties-view-params-objects.js
index 5ddca0900eb..209e0b89a6f 100644
--- a/browser/devtools/webaudioeditor/test/browser_wa_properties-view-params-objects.js
+++ b/browser/devtools/webaudioeditor/test/browser_wa_properties-view-params-objects.js
@@ -7,7 +7,7 @@
  */
 
 function spawnTest() {
-  let { target, panel } = yield initWebAudioEditor(BUFFER_AND_ARRAY_URL);
+  let [target, debuggee, panel] = yield initWebAudioEditor(BUFFER_AND_ARRAY_URL);
   let { panelWin } = panel;
   let { gFront, $, $$, EVENTS, InspectorView } = panelWin;
   let gVars = InspectorView._propsView;
diff --git a/browser/devtools/webaudioeditor/test/browser_wa_properties-view-params.js b/browser/devtools/webaudioeditor/test/browser_wa_properties-view-params.js
index d699a7ec2f2..c08838334f6 100644
--- a/browser/devtools/webaudioeditor/test/browser_wa_properties-view-params.js
+++ b/browser/devtools/webaudioeditor/test/browser_wa_properties-view-params.js
@@ -7,7 +7,7 @@
  */
 
 function spawnTest() {
-  let { target, panel } = yield initWebAudioEditor(SIMPLE_NODES_URL);
+  let [target, debuggee, panel] = yield initWebAudioEditor(SIMPLE_NODES_URL);
   let { panelWin } = panel;
   let { gFront, $, $$, EVENTS, InspectorView } = panelWin;
   let gVars = InspectorView._propsView;
diff --git a/browser/devtools/webaudioeditor/test/browser_wa_properties-view.js b/browser/devtools/webaudioeditor/test/browser_wa_properties-view.js
index 262797fd885..c84287eae86 100644
--- a/browser/devtools/webaudioeditor/test/browser_wa_properties-view.js
+++ b/browser/devtools/webaudioeditor/test/browser_wa_properties-view.js
@@ -6,7 +6,7 @@
  */
 
 function spawnTest() {
-  let { target, panel } = yield initWebAudioEditor(SIMPLE_CONTEXT_URL);
+  let [target, debuggee, panel] = yield initWebAudioEditor(SIMPLE_CONTEXT_URL);
   let { panelWin } = panel;
   let { gFront, $, $$, EVENTS, InspectorView } = panelWin;
   let gVars = InspectorView._propsView;
diff --git a/browser/devtools/webaudioeditor/test/browser_wa_reset-01.js b/browser/devtools/webaudioeditor/test/browser_wa_reset-01.js
index 566efae1411..e7151dfe7ad 100644
--- a/browser/devtools/webaudioeditor/test/browser_wa_reset-01.js
+++ b/browser/devtools/webaudioeditor/test/browser_wa_reset-01.js
@@ -7,7 +7,7 @@
  */
 
 function spawnTest() {
-  let { target, panel } = yield initWebAudioEditor(SIMPLE_CONTEXT_URL);
+  let [target, debuggee, panel] = yield initWebAudioEditor(SIMPLE_CONTEXT_URL);
   let { gFront, $ } = panel.panelWin;
 
   is($("#reload-notice").hidden, false,
diff --git a/browser/devtools/webaudioeditor/test/browser_wa_reset-02.js b/browser/devtools/webaudioeditor/test/browser_wa_reset-02.js
index 81943268f03..79242c2a16e 100644
--- a/browser/devtools/webaudioeditor/test/browser_wa_reset-02.js
+++ b/browser/devtools/webaudioeditor/test/browser_wa_reset-02.js
@@ -7,7 +7,7 @@
  */
 
 function spawnTest() {
-  let { target, panel } = yield initWebAudioEditor(SIMPLE_CONTEXT_URL);
+  let [target, debuggee, panel] = yield initWebAudioEditor(SIMPLE_CONTEXT_URL);
   let { panelWin } = panel;
   let { gFront, $ } = panelWin;
 
diff --git a/browser/devtools/webaudioeditor/test/browser_wa_reset-03.js b/browser/devtools/webaudioeditor/test/browser_wa_reset-03.js
index bbb358373e8..8ccbf9f7288 100644
--- a/browser/devtools/webaudioeditor/test/browser_wa_reset-03.js
+++ b/browser/devtools/webaudioeditor/test/browser_wa_reset-03.js
@@ -7,7 +7,7 @@
  */
 
 function spawnTest() {
-  let { target, panel } = yield initWebAudioEditor(SIMPLE_CONTEXT_URL);
+  let [target, debuggee, panel] = yield initWebAudioEditor(SIMPLE_CONTEXT_URL);
   let { panelWin } = panel;
   let { gFront, $, InspectorView } = panelWin;
 
diff --git a/browser/devtools/webaudioeditor/test/browser_wa_reset-04.js b/browser/devtools/webaudioeditor/test/browser_wa_reset-04.js
index cebb5f1d4b3..00a1eb92b4d 100644
--- a/browser/devtools/webaudioeditor/test/browser_wa_reset-04.js
+++ b/browser/devtools/webaudioeditor/test/browser_wa_reset-04.js
@@ -8,7 +8,7 @@
 function spawnTest() {
   Services.prefs.setBoolPref("devtools.command-button-frames.enabled", true);
 
-  let { target, panel, toolbox } = yield initWebAudioEditor(IFRAME_CONTEXT_URL);
+  let [target, debuggee, panel, toolbox] = yield initWebAudioEditor(IFRAME_CONTEXT_URL);
   let { gFront, $ } = panel.panelWin;
 
   is($("#reload-notice").hidden, false,
diff --git a/browser/devtools/webaudioeditor/test/browser_webaudio-actor-connect-param.js b/browser/devtools/webaudioeditor/test/browser_webaudio-actor-connect-param.js
index ad1a5c9cb6f..7239a8a6e9c 100644
--- a/browser/devtools/webaudioeditor/test/browser_webaudio-actor-connect-param.js
+++ b/browser/devtools/webaudioeditor/test/browser_webaudio-actor-connect-param.js
@@ -6,7 +6,7 @@
  */
 
 function spawnTest () {
-  let { target, front } = yield initBackend(CONNECT_PARAM_URL);
+  let [target, debuggee, front] = yield initBackend(CONNECT_PARAM_URL);
   let [, , [destNode, carrierNode, modNode, gainNode], , connectParam] = yield Promise.all([
     front.setup({ reload: true }),
     once(front, "start-context"),
diff --git a/browser/devtools/webaudioeditor/test/browser_webaudio-actor-destroy-node.js b/browser/devtools/webaudioeditor/test/browser_webaudio-actor-destroy-node.js
index 9e5feea293d..d6e15952ad3 100644
--- a/browser/devtools/webaudioeditor/test/browser_webaudio-actor-destroy-node.js
+++ b/browser/devtools/webaudioeditor/test/browser_webaudio-actor-destroy-node.js
@@ -6,7 +6,7 @@
  */
 
 function spawnTest () {
-  let { target, front } = yield initBackend(DESTROY_NODES_URL);
+  let [target, debuggee, front] = yield initBackend(DESTROY_NODES_URL);
 
   let waitUntilDestroyed = getN(front, "destroy-node", 10);
   let [, , created] = yield Promise.all([
diff --git a/browser/devtools/webaudioeditor/test/browser_webaudio-actor-simple.js b/browser/devtools/webaudioeditor/test/browser_webaudio-actor-simple.js
index 1ef29a9f999..3dd444e571c 100644
--- a/browser/devtools/webaudioeditor/test/browser_webaudio-actor-simple.js
+++ b/browser/devtools/webaudioeditor/test/browser_webaudio-actor-simple.js
@@ -6,7 +6,7 @@
  */
 
 function spawnTest () {
-  let { target, front } = yield initBackend(SIMPLE_CONTEXT_URL);
+  let [target, debuggee, front] = yield initBackend(SIMPLE_CONTEXT_URL);
   let [_, __, [destNode, oscNode, gainNode], [connect1, connect2]] = yield Promise.all([
     front.setup({ reload: true }),
     once(front, "start-context"),
diff --git a/browser/devtools/webaudioeditor/test/head.js b/browser/devtools/webaudioeditor/test/head.js
index 9e3bb78fe29..d792cbb9b8a 100644
--- a/browser/devtools/webaudioeditor/test/head.js
+++ b/browser/devtools/webaudioeditor/test/head.js
@@ -138,11 +138,12 @@ function initBackend(aUrl) {
   return Task.spawn(function*() {
     let tab = yield addTab(aUrl);
     let target = TargetFactory.forTab(tab);
+    let debuggee = target.window.wrappedJSObject;
 
     yield target.makeRemote();
 
     let front = new WebAudioFront(target.client, target.form);
-    return { target, front };
+    return [target, debuggee, front];
   });
 }
 
@@ -152,13 +153,14 @@ function initWebAudioEditor(aUrl) {
   return Task.spawn(function*() {
     let tab = yield addTab(aUrl);
     let target = TargetFactory.forTab(tab);
+    let debuggee = target.window.wrappedJSObject;
 
     yield target.makeRemote();
 
     Services.prefs.setBoolPref("devtools.webaudioeditor.enabled", true);
     let toolbox = yield gDevTools.showToolbox(target, "webaudioeditor");
     let panel = toolbox.getCurrentPanel();
-    return { target, panel, toolbox };
+    return [target, debuggee, panel, toolbox];
   });
 }
 
diff --git a/toolkit/devtools/server/actors/webaudio.js b/toolkit/devtools/server/actors/webaudio.js
index d8c867a3c3f..92894c77367 100644
--- a/toolkit/devtools/server/actors/webaudio.js
+++ b/toolkit/devtools/server/actors/webaudio.js
@@ -434,10 +434,10 @@ let WebAudioActor = exports.WebAudioActor = protocol.ActorClass({
     if (!this._initialized) {
       return;
     }
+    this.tabActor = null;
     this._initialized = false;
     off(this.tabActor, "window-destroyed", this._onGlobalDestroyed);
     off(this.tabActor, "window-ready", this._onGlobalCreated);
-    this.tabActor = null;
     this._nativeToActorID = null;
     this._callWatcher.eraseRecording();
     this._callWatcher.finalize();