This change refactors the Unity plugin's Android implementation for Native Ads to use the new Decagon SDK. It includes:

- Creating `UnityNativeTemplateAdNextgen` and related Java classes to interface with Decagon's `NativeAdLoader` and `NativeAd`.
- Forking and adapting `TemplateView` to `TemplateViewNextgen` to work with Decagon's `NativeAdView` and `MediaView`.

PiperOrigin-RevId: 917262890

Author: Mobile Ads Developer Relations

source/plugin/Assets/Plugins/Android/GoogleMobileAdsPlugin.androidlib/src/main/java/com/google/unity/ads/nativead/UnityNativeTemplateStyle.java

@@ -138,7 +138,8 @@ public int hashCode() {
         tertiaryTextStyle);
   }
 
-  private NativeTemplateStyle asNativeTemplateStyle() {
+  @NonNull
+  public NativeTemplateStyle asNativeTemplateStyle() {
     NativeTemplateStyle.Builder builder = new NativeTemplateStyle.Builder();
     if (mainBackgroundColor != null) {
       builder.withMainBackgroundColor(mainBackgroundColor);

source/plugin/Assets/Plugins/Android/GoogleMobileAdsPlugin.androidlib/src/main/java/com/google/unity/ads/nextgen/AdWrapper.java

@@ -1,6 +1,8 @@
 package com.google.unity.ads.nextgen;
 
 import com.google.android.libraries.ads.mobile.sdk.appopen.AppOpenAd;
+import com.google.android.libraries.ads.mobile.sdk.banner.BannerAd;
+import com.google.android.libraries.ads.mobile.sdk.banner.BannerAdRequest;
 import com.google.android.libraries.ads.mobile.sdk.common.AdLoadCallback;
 import com.google.android.libraries.ads.mobile.sdk.common.AdRequest;
 import com.google.android.libraries.ads.mobile.sdk.interstitial.InterstitialAd;
@@ -35,6 +37,22 @@ public static AdWrapper<AppOpenAd> forAppOpen() {
     return new AdWrapper<>(AppOpenAd::load);
   }
 
+  /** Creates a new AdWrapper for loading BannerAds. */
+  public static AdWrapper<BannerAd> forBanner() {
+    return new AdWrapper<BannerAd>(
+        new AdLoader<BannerAd>() {
+          @Override
+          public void load(AdRequest adRequest, AdLoadCallback<BannerAd> callback) {
+            if (adRequest instanceof BannerAdRequest) {
+              BannerAd.load((BannerAdRequest) adRequest, callback);
+            } else {
+              throw new IllegalArgumentException(
+                  "AdRequest must be of type BannerAdRequest for Banner Ads");
+            }
+          }
+        });
+  }
+
   /** Creates a new AdWrapper for loading InterstitialAds. */
   public static AdWrapper<InterstitialAd> forInterstitial() {
     return new AdWrapper<>(InterstitialAd::load);

source/plugin/Assets/Plugins/Android/GoogleMobileAdsPlugin.androidlib/src/main/java/com/google/unity/ads/nextgen/NativeAdOptions.java

@@ -0,0 +1,49 @@
+package com.google.unity.ads.nextgen;
+
+import com.google.android.libraries.ads.mobile.sdk.common.VideoOptions;
+
+/**
+ * DECAGON CONTEXT NOTE FOR PORTING
+ *
+ * <p>In legacy Nonagon (GMS), configuring Native Ads uses an `AdLoader.Builder` taking a Decagon
+ * separate `NativeAdOptions` class. However, Decagon removes this Class completely!
+ *
+ * <p>All properties are now set directly onto `NativeAdRequest.Builder`.
+ *
+ * <p>To avoid breaking reflection signatures where the Unity C# layer still attempts to instantiate
+ * and pass a POJO for options, we create this local Adapter Shim
+ * (`com.google.unity.ads.nextgen.NativeAdOptions`).
+ *
+ * <p>We mimic the properties provided by `GoogleMobileAds/Api/Core/NativeAdOptions.cs` and pipe
+ * them during the `loadAd` phase inside `UnityNativeTemplateAdNextgen`.
+ */
+public class NativeAdOptions {
+
+  private int mediaAspectRatio;
+  private int adChoicesPlacement;
+  private VideoOptions videoOptions;
+
+  public int getMediaAspectRatio() {
+    return mediaAspectRatio;
+  }
+
+  public void setMediaAspectRatio(int mediaAspectRatio) {
+    this.mediaAspectRatio = mediaAspectRatio;
+  }
+
+  public int getAdChoicesPlacement() {
+    return adChoicesPlacement;
+  }
+
+  public void setAdChoicesPlacement(int adChoicesPlacement) {
+    this.adChoicesPlacement = adChoicesPlacement;
+  }
+
+  public VideoOptions getVideoOptions() {
+    return videoOptions;
+  }
+
+  public void setVideoOptions(VideoOptions videoOptions) {
+    this.videoOptions = videoOptions;
+  }
+}