macOS: Fix missing "Search" item in help menu

Define the menu as the help menu directly in the the NSApplication,
since the OS built-in heuristics based on the menu name easily fails.

Fixes: QTCREATORBUG-24751
Change-Id: I9aa50a46099e295ec0c38ee8a9e88d75d41c74ad
Reviewed-by: Timur Pocheptsov <timur.pocheptsov@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>

src/libs/utils/theme/theme.cpp

@@ -253,6 +253,13 @@ void Theme::setInitialPalette(Theme *initTheme)
     initialPalette();
 }
 
+void Theme::setHelpMenu(QMenu *menu)
+{
+#ifdef Q_OS_MACOS
+    Internal::setMacOSHelpMenu(menu);
+#endif
+}
+
 QPalette Theme::initialPalette()
 {
     static QPalette palette = copyPalette(QApplication::palette());

src/libs/utils/theme/theme.h

@@ -9,6 +9,7 @@
 #include <QObject>
 
 QT_BEGIN_NAMESPACE
+class QMenu;
 class QPalette;
 class QSettings;
 QT_END_NAMESPACE
@@ -473,6 +474,8 @@ public:
 
     static void setInitialPalette(Theme *initTheme);
 
+    static void setHelpMenu(QMenu *menu);
+
 protected:
     Theme(Theme *originTheme, QObject *parent = nullptr);
     ThemePrivate *d;

src/libs/utils/theme/theme_mac.h

@@ -3,11 +3,18 @@
 
 #pragma once
 
+#include <qglobal.h>
+
+QT_BEGIN_NAMESPACE
+class QMenu;
+QT_END_NAMESPACE
+
 namespace Utils {
 namespace Internal {
 
 void forceMacAppearance(bool dark);
 bool currentAppearanceIsDark();
+void setMacOSHelpMenu(QMenu *menu);
 
 } // Internal
 } // Utils

src/libs/utils/theme/theme_mac.mm

@@ -3,7 +3,7 @@
 
 #include "theme_mac.h"
 
-#include <qglobal.h>
+#include <QMenu>
 #include <QOperatingSystemVersion>
 
 #include <AppKit/AppKit.h>
@@ -47,5 +47,10 @@ bool currentAppearanceIsDark()
     return !currentAppearanceMatches(false /*==light*/);
 }
 
+void setMacOSHelpMenu(QMenu *menu)
+{
+    NSApp.helpMenu = menu->toNSMenu();
+}
+
 } // Internal
 } // Utils

src/plugins/coreplugin/mainwindow.cpp

@@ -514,6 +514,7 @@ void MainWindow::registerDefaultContainers()
     ac = ActionManager::createMenu(Constants::M_HELP);
     menubar->addMenu(ac, Constants::G_HELP);
     ac->menu()->setTitle(tr("&Help"));
+    Theme::setHelpMenu(ac->menu());
     ac->appendGroup(Constants::G_HELP_HELP);
     ac->appendGroup(Constants::G_HELP_SUPPORT);
     ac->appendGroup(Constants::G_HELP_ABOUT);