Fix theme native object collection in Android S

Previously, in Android P through R, Robolectric would clean up native themes
from the registry when AssetManager.nativeThemeDestroy was called by the
ThemeImpl finalizer. However, starting in Android S,
AssetManager.nativeThemeDestroy does not exist any more.

As a workaround, hook into the AssetManager.releaseTheme method to free the
theme from the registry. Longer term we may want to have the theme destruction
logic be part of AssetManager.nativeDestroy, where all themes can potentially
be freed in one fell swoop.

This should fix #6872. Thanks to @calvarez-ov for reporting the issue and
helping debug :)

PiperOrigin-RevId: 411169531

robolectric/src/test/java/org/robolectric/shadows/ShadowThemeTest.java

@@ -9,21 +9,30 @@
 import android.content.res.TypedArray;
 import android.content.res.XmlResourceParser;
 import android.graphics.drawable.ColorDrawable;
+import android.os.Build.VERSION_CODES;
 import android.os.Bundle;
 import android.util.AttributeSet;
 import android.util.Xml;
 import android.view.View;
 import android.widget.Button;
 import androidx.test.core.app.ApplicationProvider;
 import androidx.test.ext.junit.runners.AndroidJUnit4;
+import java.lang.ref.WeakReference;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicLong;
+import java.util.function.Supplier;
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.robolectric.R;
 import org.robolectric.Robolectric;
 import org.robolectric.android.controller.ActivityController;
+import org.robolectric.annotation.Config;
+import org.robolectric.res.android.Registries;
 import org.robolectric.shadows.testing.TestActivity;
+import org.robolectric.util.ReflectionHelpers;
 import org.xmlpull.v1.XmlPullParser;
 
 @RunWith(AndroidJUnit4.class)
@@ -272,6 +281,40 @@ public void shouldApplyFromStyleAttribute() {
     assertThat(button.getLayoutParams().width).isEqualTo(42); // comes via style attr
   }
 
+  @Test
+  @Config(minSdk = VERSION_CODES.N)
+  public void shouldFreeNativeObjectInRegistry() {
+    final AtomicLong themeId = new AtomicLong(0);
+    Supplier<Theme> themeSupplier =
+        () -> {
+          Theme theme = resources.newTheme();
+          long nativeId =
+              ReflectionHelpers.getField(ReflectionHelpers.getField(theme, "mThemeImpl"), "mTheme");
+          themeId.set(nativeId);
+          return theme;
+        };
+
+    WeakReference<Theme> weakRef = new WeakReference<>(themeSupplier.get());
+    awaitFinalized(weakRef);
+    assertThat(Registries.NATIVE_THEME9_REGISTRY.peekNativeObject(themeId.get())).isNull();
+  }
+
+  private static <T> void awaitFinalized(WeakReference<T> weakRef) {
+    final CountDownLatch latch = new CountDownLatch(1);
+    long deadline = System.nanoTime() + TimeUnit.SECONDS.toNanos(5);
+    while (System.nanoTime() < deadline) {
+      if (weakRef.get() == null) {
+        return;
+      }
+      try {
+        System.gc();
+        latch.await(100, TimeUnit.MILLISECONDS);
+      } catch (InterruptedException e) {
+        throw new AssertionError(e);
+      }
+    }
+  }
+
   ////////////////////////////
 
   private XmlResourceParser getFirstElementAttrSet(int resId) throws Exception {

shadows/framework/src/main/java/org/robolectric/shadows/ShadowArscAssetManager10.java

@@ -3,6 +3,7 @@
 import static android.os.Build.VERSION_CODES.P;
 import static android.os.Build.VERSION_CODES.Q;
 import static android.os.Build.VERSION_CODES.R;
+import static android.os.Build.VERSION_CODES.S;
 import static org.robolectric.res.android.ApkAssetsCookie.K_INVALID_COOKIE;
 import static org.robolectric.res.android.ApkAssetsCookie.kInvalidCookie;
 import static org.robolectric.res.android.Asset.SEEK_CUR;
@@ -1610,6 +1611,12 @@ protected static void nativeThemeDestroy(long theme_ptr) {
     Registries.NATIVE_THEME9_REGISTRY.unregister(theme_ptr);
   }
 
+  @Implementation(minSdk = S)
+  protected void releaseTheme(long ptr) {
+    Registries.NATIVE_THEME9_REGISTRY.unregister(ptr);
+    reflector(AssetManagerReflector.class, realAssetManager).releaseTheme(ptr);
+  }
+
   // static void NativeThemeApplyStyle(JNIEnv* env, jclass /*clazz*/, jlong ptr, jlong theme_ptr,
   //                                   jint resid, jboolean force) {
   @Implementation(minSdk = P)
@@ -1936,6 +1943,9 @@ interface AssetManagerReflector {
     @Static
     @Direct
     void createSystemAssetsInZygoteLocked();
+
+    @Direct
+    void releaseTheme(long ptr);
   }
 }
 ; // namespace android