cmake: Add preset to build flutter frontend standalone

It can't be build in conjuction with the QtWidgets one, since
that would mean using QAction from Qt and requiring a QApplication.

Instead just build the flutter frontend.

CMakePresets.json

@@ -11,7 +11,7 @@
                 "KDDockWidgets_DEVELOPER_MODE": "ON",
                 "CMAKE_EXPORT_COMPILE_COMMANDS": "ON",
                 "KDDockWidgets_FUZZER": "OFF",
-                "KDDockWidgets_FRONTENDS": "qtwidgets;qtquick;dummy;flutter"
+                "KDDockWidgets_FRONTENDS": "qtwidgets;qtquick;dummy"
             },
             "warnings": {
                 "uninitialized": true
@@ -29,7 +29,24 @@
                 "CMAKE_EXPORT_COMPILE_COMMANDS": "ON",
                 "KDDockWidgets_FUZZER": "OFF",
                 "ECM_ENABLE_SANITIZERS": "'address;undefined'",
-                "KDDockWidgets_FRONTENDS": "qtwidgets;qtquick;dummy;flutter"
+                "KDDockWidgets_FRONTENDS": "qtwidgets;qtquick;dummy"
+            },
+            "warnings": {
+                "uninitialized": true
+            }
+        },
+        {
+            "name": "dev-flutter",
+            "displayName": "dev-flutter",
+            "generator": "Ninja",
+            "binaryDir": "${sourceDir}/build-dev-flutter",
+            "cacheVariables": {
+                "CMAKE_BUILD_TYPE": "Debug",
+                "KDDockWidgets_DEVELOPER_MODE": "ON",
+                "CMAKE_EXPORT_COMPILE_COMMANDS": "ON",
+                "KDDockWidgets_FUZZER": "OFF",
+                "KDDockWidgets_FRONTENDS": "flutter",
+                "ECM_ENABLE_SANITIZERS": "'address;undefined'"
             },
             "warnings": {
                 "uninitialized": true
@@ -394,4 +411,4 @@
             }
         }
     ]
-}
+}

src/Platform.cpp

@@ -135,6 +135,8 @@ void Platform::tests_initPlatform(int &argc, char **argv, KDDockWidgets::Fronten
 #ifdef KDDW_FRONTEND_FLUTTER
         // TODOm4: This needs to be called from Dart
         platform = nullptr;
+        Q_UNUSED(argc);
+        Q_UNUSED(argv);
 #endif
         break;
     }

src/dummy/views/Stack_dummy.cpp

@@ -19,12 +19,6 @@
 #include "Window.h"
 #include "private/View_p.h"
 
-#include <QMouseEvent>
-#include <QTabBar>
-#include <QHBoxLayout>
-#include <QAbstractButton>
-#include <QMenu>
-
 using namespace KDDockWidgets;
 using namespace KDDockWidgets::Views;