Replace `window` references in ActionCable with `self`

Before this change, attempting to use ActionCable inside a web worker
would result in an exception being thrown:
```
ReferenceError: window is not defined
```

By replacing the `window` reference with `self`, which is available in
both a window context and a worker context, we can avoid this error.

Ref:
https://developer.mozilla.org/en-US/docs/Web/API/Window/self

3 files changed, 8 insertions, 8 deletions

diff --git a/actioncable/app/assets/javascripts/action_cable.js b/actioncable/app/assets/javascripts/action_cable.js
index a68c76f299..2b51eadb9e 100644
--- a/actioncable/app/assets/javascripts/action_cable.js
+++ b/actioncable/app/assets/javascripts/action_cable.js
@@ -3,8 +3,8 @@
 })(this, function(exports) {
   "use strict";
   var adapters = {
-    logger: window.console,
-    WebSocket: window.WebSocket
+    logger: self.console,
+    WebSocket: self.WebSocket
   };
   var logger = {
     log: function log() {
diff --git a/actioncable/app/javascript/action_cable/adapters.js b/actioncable/app/javascript/action_cable/adapters.js
index 9ba6d338ee..4de8131438 100644
--- a/actioncable/app/javascript/action_cable/adapters.js
+++ b/actioncable/app/javascript/action_cable/adapters.js
@@ -1,4 +1,4 @@
 export default {
-  logger: window.console,
-  WebSocket: window.WebSocket
+  logger: self.console,
+  WebSocket: self.WebSocket
 }
diff --git a/actioncable/test/javascript/src/unit/action_cable_test.js b/actioncable/test/javascript/src/unit/action_cable_test.js
index daad900aca..83426fa32e 100644
--- a/actioncable/test/javascript/src/unit/action_cable_test.js
+++ b/actioncable/test/javascript/src/unit/action_cable_test.js
@@ -6,14 +6,14 @@ const {module, test} = QUnit
 module("ActionCable", () => {
   module("Adapters", () => {
     module("WebSocket", () => {
-      test("default is window.WebSocket", assert => {
-        assert.equal(ActionCable.adapters.WebSocket, window.WebSocket)
+      test("default is self.WebSocket", assert => {
+        assert.equal(ActionCable.adapters.WebSocket, self.WebSocket)
       })
     })
 
     module("logger", () => {
-      test("default is window.console", assert => {
-        assert.equal(ActionCable.adapters.logger, window.console)
+      test("default is self.console", assert => {
+        assert.equal(ActionCable.adapters.logger, self.console)
       })
     })
   })