[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 cdbe2d17aafc72bb6c0e8f10006e82ad9da548e3..d98a2b97ea141632fe5956be573f7bccb5f533aa 100644
--- a/chrome/browser/ui/cocoa/browser_window_controller.h
+++ b/chrome/browser/ui/cocoa/browser_window_controller.h
@@ -65,6 +65,10 @@ namespace extensions {
 class Command;
 }
 
+namespace {
+class OmniboxPopupModelObserverBridge;
+}
+
 constexpr const gfx::Size kMinCocoaTabbedWindowSize(400, 272);
 constexpr const gfx::Size kMinCocoaPopupWindowSize(100, 122);
 
@@ -197,6 +201,10 @@ constexpr const gfx::Size kMinCocoaPopupWindowSize(100, 122);
   // 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