Implement PlatformViewsController.createOverlaySurface (flutter#19226)

Author: jason-simmons

shell/platform/android/io/flutter/plugin/platform/PlatformViewsController.java

@@ -9,6 +9,9 @@
 
 import android.annotation.TargetApi;
 import android.content.Context;
+import android.graphics.PixelFormat;
+import android.hardware.HardwareBuffer;
+import android.media.ImageReader;
 import android.os.Build;
 import android.util.DisplayMetrics;
 import android.util.Log;
@@ -17,6 +20,7 @@
 import androidx.annotation.NonNull;
 import androidx.annotation.UiThread;
 import androidx.annotation.VisibleForTesting;
+import io.flutter.embedding.android.FlutterImageView;
 import io.flutter.embedding.engine.FlutterOverlaySurface;
 import io.flutter.embedding.engine.dart.DartExecutor;
 import io.flutter.embedding.engine.systemchannels.PlatformViewsChannel;
@@ -71,6 +75,12 @@ public class PlatformViewsController implements PlatformViewsAccessibilityDelega
   // it is associated with(e.g if a platform view creates other views in the same virtual display.
   private final HashMap<Context, View> contextToPlatformView;
 
+  // Map of unique IDs to views that render overlay layers.
+  private HashMap<Long, FlutterImageView> overlayLayerViews;
+
+  // Next available unique ID for use in overlayLayerViews;
+  private long nextOverlayLayerId = 0;
+
   private final PlatformViewsChannel.PlatformViewsHandler channelHandler =
       new PlatformViewsChannel.PlatformViewsHandler() {
         @TargetApi(Build.VERSION_CODES.JELLY_BEAN_MR1)
@@ -283,6 +293,7 @@ public PlatformViewsController() {
     vdControllers = new HashMap<>();
     accessibilityEventsDelegate = new AccessibilityEventsDelegate();
     contextToPlatformView = new HashMap<>();
+    overlayLayerViews = new HashMap<>();
   }
 
   /**
@@ -552,7 +563,25 @@ public void onEndFrame() {
   }
 
   public FlutterOverlaySurface createOverlaySurface() {
-    // TODO: Implement this method. https://github.com/flutter/flutter/issues/58288
-    return null;
+    ImageReader imageReader;
+    if (android.os.Build.VERSION.SDK_INT >= 29) {
+      imageReader =
+          ImageReader.newInstance(
+              flutterView.getWidth(),
+              flutterView.getHeight(),
+              PixelFormat.RGBA_8888,
+              2,
+              HardwareBuffer.USAGE_GPU_SAMPLED_IMAGE | HardwareBuffer.USAGE_GPU_COLOR_OUTPUT);
+    } else {
+      imageReader =
+          ImageReader.newInstance(
+              flutterView.getWidth(), flutterView.getHeight(), PixelFormat.RGBA_8888, 2);
+    }
+
+    FlutterImageView imageView = new FlutterImageView(flutterView.getContext(), imageReader);
+    long id = nextOverlayLayerId++;
+    overlayLayerViews.put(id, imageView);
+
+    return new FlutterOverlaySurface(id, imageReader.getSurface());
   }
 }