Optimizing performance by avoiding multiple GC operations caused by multiple surface destruction notifications

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

@@ -370,19 +370,20 @@ public void surfaceChanged(int width, int height) {
    * android.view.TextureView.SurfaceTextureListener}
    */
   public void stopRenderingToSurface() {
-    flutterJNI.onSurfaceDestroyed();
-
-    surface = null;
+    if (surface != null) {
+      flutterJNI.onSurfaceDestroyed();
+
+      // TODO(mattcarroll): the source of truth for this call should be FlutterJNI, which is where
+      // the call to onFlutterUiDisplayed() comes from. However, no such native callback exists yet,
+      // so until the engine and FlutterJNI are configured to call us back when rendering stops,
+      // we will manually monitor that change here.
+      if (isDisplayingFlutterUi) {
+        flutterUiDisplayListener.onFlutterUiNoLongerDisplayed();
+      }
 
-    // TODO(mattcarroll): the source of truth for this call should be FlutterJNI, which is where
-    // the call to onFlutterUiDisplayed() comes from. However, no such native callback exists yet,
-    // so until the engine and FlutterJNI are configured to call us back when rendering stops,
-    // we will manually monitor that change here.
-    if (isDisplayingFlutterUi) {
-      flutterUiDisplayListener.onFlutterUiNoLongerDisplayed();
+      isDisplayingFlutterUi = false;
+      surface = null;
     }
-
-    isDisplayingFlutterUi = false;
   }
 
   /**

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

@@ -393,4 +393,20 @@ public void onTrimMemory(int level) {
     // Verify behavior under test.
     assertEquals(1, invocationCount.get());
   }
+
+  @Test
+  public void itDoesDispatchSurfaceDestructionNotificationOnlyOnce() {
+    // Setup the test.
+    FlutterRenderer flutterRenderer = new FlutterRenderer(fakeFlutterJNI);
+
+    flutterRenderer.startRenderingToSurface(fakeSurface, /*keepCurrentSurface=*/ false);
+
+    // Execute the behavior under test.
+    // Simulate calling |FlutterRenderer#stopRenderingToSurface| twice with different code paths.
+    flutterRenderer.stopRenderingToSurface();
+    flutterRenderer.stopRenderingToSurface();
+
+    // Verify behavior under test.
+    verify(fakeFlutterJNI, times(1)).onSurfaceDestroyed();
+  }
 }