[Extensions UI] Handle multiple warning bubbles racing to show

chrome/browser/ui/toolbar/toolbar_actions_bar.h

Index: chrome/browser/ui/toolbar/toolbar_actions_bar.h
diff --git a/chrome/browser/ui/toolbar/toolbar_actions_bar.h b/chrome/browser/ui/toolbar/toolbar_actions_bar.h
index b4d36e08185ad8dfc8056e75ae086516d627daae..388b31d9a4ca1475b2a29d0faaa0aa4411731cf6 100644
--- a/chrome/browser/ui/toolbar/toolbar_actions_bar.h
+++ b/chrome/browser/ui/toolbar/toolbar_actions_bar.h
@@ -249,6 +249,7 @@ class ToolbarActionsBar : public ToolbarActionsModel::Observer,
     return popped_out_action_;
   }
   bool in_overflow_mode() const { return main_bar_ != nullptr; }
+  bool is_showing_bubble() const { return is_showing_bubble_; }
 
   ToolbarActionsBarDelegate* delegate_for_test() { return delegate_; }
 
@@ -293,8 +294,7 @@ class ToolbarActionsBar : public ToolbarActionsModel::Observer,
   void ReorderActions();
 
   // Shows an extension message bubble, if any should be shown.
-  void MaybeShowExtensionBubble(
-      std::unique_ptr<extensions::ExtensionMessageBubbleController> controller);
+  void MaybeShowExtensionBubble();
 
   // The delegate for this object (in a real build, this is the view).
   ToolbarActionsBarDelegate* delegate_;