diff --git a/background.html b/background.html
index 92a2e229b..dc9aed074 100644
--- a/background.html
+++ b/background.html
@@ -346,7 +346,6 @@
   <script type='text/javascript' src='js/expiring_messages.js'></script>
   <script type='text/javascript' src='js/expiring_tap_to_view_messages.js'></script>
 
-  <script type='text/javascript' src='js/chromium.js'></script>
   <script type='text/javascript' src='js/message_controller.js'></script>
 
   <script type='text/javascript' src='js/views/react_wrapper_view.js'></script>
diff --git a/js/chromium.js b/js/chromium.js
deleted file mode 100644
index a44c52ed2..000000000
--- a/js/chromium.js
+++ /dev/null
@@ -1,13 +0,0 @@
-/* global extension: false */
-
-// eslint-disable-next-line func-names
-(function() {
-  // Browser specific functions for Chrom*
-  window.extension = window.extension || {};
-
-  extension.windows = {
-    onClosed(callback) {
-      window.addEventListener('beforeunload', callback);
-    },
-  };
-})();
diff --git a/ts/views/conversation_view.ts b/ts/views/conversation_view.ts
index d6d31e1c3..554730146 100644
--- a/ts/views/conversation_view.ts
+++ b/ts/views/conversation_view.ts
@@ -377,10 +377,6 @@ Whisper.ConversationView = Whisper.View.extend({
       props: this.getPropsForAttachmentList(),
     });
 
-    window.extension.windows.onClosed(() => {
-      this.unload('windows closed');
-    });
-
     this.setupHeader();
     this.setupTimeline();
     this.setupCompositionArea({ attachmentListEl: attachmentListEl[0] });
diff --git a/ts/window.d.ts b/ts/window.d.ts
index 785e23831..7da4eb3e3 100644
--- a/ts/window.d.ts
+++ b/ts/window.d.ts
@@ -49,7 +49,6 @@ declare global {
     _: typeof Underscore;
     $: typeof jQuery;
 
-    extension: any;
     moment: any;
     imageToBlurHash: any;
     autoOrientImage: any;