[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 c14373321321907ea2980d168c8e7f0c94275832..32f71fc82416793a601f50c63f79b420af05c917 100644
--- a/chrome/browser/ui/cocoa/browser_window_controller.h
+++ b/chrome/browser/ui/cocoa/browser_window_controller.h
@@ -64,6 +64,10 @@ namespace extensions {
 class Command;
 }
 
+namespace {
+class OmniboxPopupModelObserverBridge;
+}
+
 @interface BrowserWindowController
     : TabWindowController<BookmarkBarControllerDelegate,
                           ViewResizer,
@@ -201,6 +205,10 @@ class Command;
   // handle.
   std::unique_ptr<ExtensionKeybindingRegistryCocoa>
       extension_keybinding_registry_;
+
+  // Observes whether the omnibox popup is shown or hidden.
+  std::unique_ptr<OmniboxPopupModelObserverBridge>
+      omniboxPopupModelObserverBridge_;
 }
 
 // A convenience class method which gets the |BrowserWindowController| for a