Add SurfaceProducer#onSurfaceAvailable, deprecate onSurfaceCreated.

shell/platform/android/io/flutter/embedding/engine/renderer/FlutterRenderer.java

@@ -108,8 +108,9 @@ public FlutterRenderer(@NonNull FlutterJNI flutterJNI) {
               public void onResume(@NonNull LifecycleOwner owner) {
                 Log.v(TAG, "onResume called; notifying SurfaceProducers");
                 for (ImageReaderSurfaceProducer producer : imageReaderProducers) {
-                  if (producer.callback != null) {
-                    producer.callback.onSurfaceCreated();
+                  if (producer.callback != null && producer.notifiedDestroy) {
+                    producer.notifiedDestroy = false;
+                    producer.callback.onSurfaceAvailable();
                   }
                 }
               }
@@ -462,6 +463,13 @@ final class ImageReaderSurfaceProducer
     // will be produced at that size.
     private boolean createNewReader = true;
 
+    /**
+     * Stores whether {@link Callback#onSurfaceDestroyed()} was previously invoked.
+     *
+     * <p>Used to avoid signaling {@link Callback#onSurfaceAvailable()} unnecessarily.
+     */
+    private boolean notifiedDestroy = false;
+
     // State held to track latency of various stages.
     private long lastDequeueTime = 0;
     private long lastQueueTime = 0;
@@ -689,6 +697,7 @@ public void onTrimMemory(int level) {
       cleanup();
       createNewReader = true;
       if (this.callback != null) {
+        notifiedDestroy = true;
         this.callback.onSurfaceDestroyed();
       }
     }

shell/platform/android/io/flutter/view/TextureRegistry.java

@@ -96,8 +96,8 @@ interface SurfaceProducer extends TextureEntry {
 
     /**
      * Sets a callback that is notified when a previously created {@link Surface} returned by {@link
-     * SurfaceProducer#getSurface()} is no longer valid, either due to being destroyed or being
-     * changed.
+     * SurfaceProducer#getSurface()} is no longer valid due to being destroyed, or a new surface is
+     * now available (after the previous one was destroyed) for rendering.
      *
      * @param callback The callback to notify, or null to remove the callback.
      */
@@ -106,18 +106,65 @@ interface SurfaceProducer extends TextureEntry {
     /** Callback invoked by {@link #setCallback(Callback)}. */
     interface Callback {
       /**
-       * Invoked when a previous surface is now invalid and a new surface is now available.
+       * An alias for {@link Callback#onSurfaceAvailable()} with a less accurate name.
+       *
+       * @deprecated Override and use {@link Callback#onSurfaceAvailable()} instead.
+       */
+      @Deprecated(since = "Flutter 3.27", forRemoval = true)
+      default void onSurfaceCreated() {}
+
+      /**
+       * Invoked when an Android application is resumed after {@link Callback#onSurfaceDestroyed()}.
        *
-       * <p>Typically plugins will use this callback as a signal to redraw, such as due to the
-       * texture being resized, the format being changed, or the application being resumed after
-       * being suspended in the background.
+       * <p>Applications should now call {@link SurfaceProducer#getSurface()} to get a new
+       * {@link Surface}, as the previous one was destroyed and released as a result of a low memory
+       * event from the Android OS.
+       *
+       * <pre>
+       * {@code
+       * void example(SurfaceProducer producer) {
+       *   producer.setCallback(new SurfaceProducer.Callback() {
+       *     @override
+       *     public void onSurfaceAvailable() {
+       *       Surface surface = producer.getSurface();
+       *       redrawOrUse(surface);
+       *     }
+       *
+       *     // ...
+       *   });
+       * }
+       * }
+       * </pre>
        */
-      void onSurfaceCreated();
+      default void onSurfaceAvailable() {
+        this.onSurfaceCreated();
+      }
 
       /**
-       * Invoked when a previous surface is now invalid.
+       * Invoked when a {@link Surface} returned by {@link SurfaceProducer#getSurface()} is invalid.
+       *
+       * <p>In a low memory environment, the Android OS will signal to Flutter to release resources,
+       * such as surfaces, that are not currently in use, such as when the application is in the
+       * background, and this method is subsequently called to notify a plugin author to stop
+       * using or rendering to the last surface.
+       *
+       * <p>Use {@link Callback#onSurfaceAvailable()} to be notified to resume rendering.
+       *
+       * <pre>
+       * {@code
+       * void example(SurfaceProducer producer) {
+       *   producer.setCallback(new SurfaceProducer.Callback() {
+       *     @override
+       *     public void onSurfaceDestroyed() {
+       *       // Store information about the last frame, if necessary.
+       *       // Potentially release other dependent resources.
+       *     }
        *
-       * <p>Typically plugins will use this callback as a signal to release resources.
+       *     // ...
+       *   });
+       * }
+       * }
+       * </pre>
        */
       void onSurfaceDestroyed();
     }

shell/platform/android/test/io/flutter/embedding/engine/renderer/FlutterRendererTest.java

@@ -762,7 +762,7 @@ public void ImageReaderSurfaceProducerIsCreatedOnLifecycleResume() throws Except
     TextureRegistry.SurfaceProducer.Callback callback =
         new TextureRegistry.SurfaceProducer.Callback() {
           @Override
-          public void onSurfaceCreated() {
+          public void onSurfaceAvailable() {
             latch.countDown();
           }
 
@@ -771,6 +771,9 @@ public void onSurfaceDestroyed() {}
         };
     producer.setCallback(callback);
 
+    // Trim memory.
+    ((FlutterRenderer.ImageReaderSurfaceProducer) producer).onTrimMemory(40);
+
     // Trigger a resume.
     ((LifecycleRegistry) ProcessLifecycleOwner.get().getLifecycle())
         .setCurrentState(Lifecycle.State.RESUMED);