diff --git a/chrome/browser/ui/toolbar/app_menu_model.cc b/chrome/browser/ui/toolbar/app_menu_model.cc
index 6c96886..ef5ab4c3 100644
--- a/chrome/browser/ui/toolbar/app_menu_model.cc
+++ b/chrome/browser/ui/toolbar/app_menu_model.cc
@@ -244,11 +244,12 @@
       uma_action_recorded_(false),
       provider_(provider),
       browser_(browser),
-      app_menu_icon_controller_(app_menu_icon_controller) {}
+      app_menu_icon_controller_(app_menu_icon_controller) {
+  DCHECK(browser_);
+}
 
 AppMenuModel::~AppMenuModel() {
-  if (browser_)  // Null in Cocoa tests.
-    browser_->tab_strip_model()->RemoveObserver(this);
+  browser_->tab_strip_model()->RemoveObserver(this);
 }
 
 void AppMenuModel::Init() {