Add device preview

.vscode/launch.json

@@ -40,5 +40,12 @@
                 "--web-port=8080"
             ],
         },
+        {
+            "name": "device_preview",
+            "cwd": "example",
+            "request": "launch",
+            "type": "dart",
+            "program": "lib/main_device_preview.dart"
+        },
     ],
 }

.vscode/settings.json

@@ -21,6 +21,7 @@
     "LPOSVERSIONINFO",
     "lpsz",
     "LRESULT",
+    "LTWH",
     "MAXIMIZEBOX",
     "microtask",
     "MINIMIZEBOX",
@@ -52,6 +53,7 @@
     "Unpair",
     "Unpairing",
     "unwatch",
+    "USERPROFILE",
     "uuidstr",
     "winrt",
     "WNDCLASS",