Revert of [Mac] The infobar's top arrow should be hidden while the omnibox popup is shown

chrome/browser/ui/cocoa/browser_window_controller.h

Index: chrome/browser/ui/cocoa/browser_window_controller.h
diff --git a/chrome/browser/ui/cocoa/browser_window_controller.h b/chrome/browser/ui/cocoa/browser_window_controller.h
index d98a2b97ea141632fe5956be573f7bccb5f533aa..cdbe2d17aafc72bb6c0e8f10006e82ad9da548e3 100644
--- a/chrome/browser/ui/cocoa/browser_window_controller.h
+++ b/chrome/browser/ui/cocoa/browser_window_controller.h
@@ -63,10 +63,6 @@
 
 namespace extensions {
 class Command;
-}
-
-namespace {
-class OmniboxPopupModelObserverBridge;
 }
 
 constexpr const gfx::Size kMinCocoaTabbedWindowSize(400, 272);
@@ -201,10 +197,6 @@
   // handle.
   std::unique_ptr<ExtensionKeybindingRegistryCocoa>
       extensionKeybindingRegistry_;
-
-  // Observes whether the omnibox popup is shown or hidden.
-  std::unique_ptr<OmniboxPopupModelObserverBridge>
-      omniboxPopupModelObserverBridge_;
 }
 
 // A convenience class method which gets the |BrowserWindowController| for a