Request another frame in ImageReaderSurfaceProducer.dequeueImage if more images are pending in the queue

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

@@ -553,6 +553,10 @@ boolean canPrune() {
         return imageQueue.isEmpty() && lastReaderDequeuedFrom != this;
       }
 
+      boolean imageQueueIsEmpty() {
+        return imageQueue.isEmpty();
+      }
+
       void close() {
         closed = true;
         if (VERBOSE_LOGS) {
@@ -630,6 +634,7 @@ void onImage(ImageReader reader, Image image) {
 
     PerImage dequeueImage() {
       PerImage r = null;
+      boolean hasPendingImages = false;
       synchronized (lock) {
         for (PerImageReader reader : imageReaderQueue) {
           r = reader.dequeueImage();
@@ -679,6 +684,21 @@ PerImage dequeueImage() {
           break;
         }
         pruneImageReaderQueue();
+        for (PerImageReader reader : imageReaderQueue) {
+          if (!reader.imageQueueIsEmpty()) {
+            hasPendingImages = true;
+            break;
+          }
+        }
+      }
+      if (hasPendingImages) {
+        // Request another frame to ensure that images are consumed until the queue is empty.
+        handler.post(
+            () -> {
+              if (!released) {
+                scheduleEngineFrame();
+              }
+            });
       }
       return r;
     }
@@ -1245,7 +1265,8 @@ private void registerImageTexture(
     flutterJNI.registerImageTexture(textureId, imageTexture);
   }
 
-  private void scheduleEngineFrame() {
+  @VisibleForTesting
+  /* package */ void scheduleEngineFrame() {
     flutterJNI.scheduleFrame();
   }
 

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

@@ -826,4 +826,43 @@ public void onSurfaceDestroyed() {}
     // Verify.
     latch.await();
   }
+
+  @Test
+  public void ImageReaderSurfaceProducerSchedulesFrameIfQueueNotEmpty() throws Exception {
+    FlutterRenderer flutterRenderer = spy(engineRule.getFlutterEngine().getRenderer());
+    TextureRegistry.SurfaceProducer producer = flutterRenderer.createSurfaceProducer();
+    FlutterRenderer.ImageReaderSurfaceProducer texture =
+        (FlutterRenderer.ImageReaderSurfaceProducer) producer;
+    texture.disableFenceForTest();
+    texture.setSize(1, 1);
+
+    // Render two frames.
+    for (int i = 0; i < 2; i++) {
+      Surface surface = texture.getSurface();
+      assertNotNull(surface);
+      Canvas canvas = surface.lockHardwareCanvas();
+      canvas.drawARGB(255, 255, 0, 0);
+      surface.unlockCanvasAndPost(canvas);
+      shadowOf(Looper.getMainLooper()).idle();
+    }
+
+    // Each enqueue of an image should result in a call to scheduleEngineFrame.
+    verify(flutterRenderer, times(2)).scheduleEngineFrame();
+
+    // Consume the first image.
+    Image image = texture.acquireLatestImage();
+    shadowOf(Looper.getMainLooper()).idle();
+
+    // The dequeue should call scheduleEngineFrame because another image
+    // remains in the queue.
+    verify(flutterRenderer, times(3)).scheduleEngineFrame();
+
+    // Consume the second image.
+    image = texture.acquireLatestImage();
+    shadowOf(Looper.getMainLooper()).idle();
+
+    // The dequeue should not call scheduleEngineFrame because the queue
+    // is now empty.
+    verify(flutterRenderer, times(3)).scheduleEngineFrame();
+  }
 }