Add LibraryContentProvider for NativeAdvertisement

Sources/AdMobUI/DeveloperToolsSupport/LibraryContentProvider.swift

@@ -0,0 +1,51 @@
+//
+//  LibraryContentProvider.swift
+//  AdMobUI
+//
+//  Created by Takashi Ushikoshi on 2026/07/31.
+//
+//
+
+import DeveloperToolsSupport
+import SwiftUI
+@preconcurrency import GoogleMobileAds
+
+struct LibraryContentProvider: DeveloperToolsSupport.LibraryContentProvider {
+    @LibraryContentBuilder
+    var views: [LibraryItem] {
+        LibraryItem(
+            NativeAdvertisement(adUnitId: /*@START_MENU_TOKEN@*/"Your Ad Unit ID"/*@END_MENU_TOKEN@*/) { advertisementPhase in
+                if let nativeAd = advertisementPhase.nativeAd {
+                    /*@START_MENU_TOKEN@*//*@PLACEHOLDER=Ad Content@*/ /*@END_MENU_TOKEN@*/
+                }
+            },
+            title: "Native Advertisement",
+            category: .other
+        )
+
+        LibraryItem(
+            NativeAdvertisement(adUnitId: /*@START_MENU_TOKEN@*/"Your Ad Unit ID"/*@END_MENU_TOKEN@*/) { advertisementPhase in
+                switch advertisementPhase {
+                case .empty:
+                    /*@START_MENU_TOKEN@*//*@PLACEHOLDER=Content while loading@*/EmptyView()/*@END_MENU_TOKEN@*/
+
+                case .success(let loadedAd):
+                    VStack(alignment: .leading) {
+                        if let headline = loadedAd.headline {
+                            Text(headline)
+                                .font(.headline)
+                                .nativeAdElement(.headline)
+                        }
+
+                        AdvertisementMedia(mediaContent: loadedAd.mediaContent)
+                    }
+
+                case .failure:
+                    /*@START_MENU_TOKEN@*//*@PLACEHOLDER=Content when load fails@*/EmptyView()/*@END_MENU_TOKEN@*/
+                }
+            },
+            title: "Native Advertisement (Full Phase Handling)",
+            category: .other
+        )
+    }
+}