Eagerly remove the PlatformView from the view hierarchy on Android (#43423)

Eagerly remove the PlatformView from the view hierarchy on Android.

Fixes [#107297](flutter/flutter#107297)

## Pre-launch Checklist

- [x] I read the [Contributor Guide] and followed the process outlined
there for submitting PRs.
- [x] I read the [Tree Hygiene] wiki page, which explains my
responsibilities.
- [x] I read and followed the [Flutter Style Guide] and the [C++,
Objective-C, Java style guides].
- [x] I listed at least one issue that this PR fixes in the description
above.
- [x] I added new tests to check the change I am making or feature I am
adding, or Hixie said the PR is test-exempt. See [testing the engine]
for instructions on writing and running engine tests.
- [x] I updated/added relevant documentation (doc comments with `///`).
- [x] I signed the [CLA].
- [x] All existing and new tests are passing.

Author: johnmccutchan

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

@@ -232,14 +232,22 @@ public void dispose(int viewId) {
             Log.e(TAG, "Disposing unknown platform view with id: " + viewId);
             return;
           }
+          if (platformView.getView() != null) {
+            final View embeddedView = platformView.getView();
+            final ViewGroup pvParent = (ViewGroup) embeddedView.getParent();
+            if (pvParent != null) {
+              // Eagerly remove the embedded view from the PlatformViewWrapper.
+              // Without this call, we see some crashes because removing the view
+              // is used as a signal to stop processing.
+              pvParent.removeView(embeddedView);
+            }
+          }
           platformViews.remove(viewId);
-
           try {
             platformView.dispose();
           } catch (RuntimeException exception) {
             Log.e(TAG, "Disposing platform view threw an exception", exception);
           }
-
           if (usesVirtualDisplay(viewId)) {
             final VirtualDisplayController vdController = vdControllers.get(viewId);
             final View embeddedView = vdController.getView();
@@ -581,7 +589,8 @@ private long configureForVirtualDisplay(
   // Configures the view for Texture Layer Hybrid Composition mode, returning the associated
   // texture ID.
   @TargetApi(23)
-  private long configureForTextureLayerComposition(
+  @VisibleForTesting(otherwise = VisibleForTesting.PACKAGE_PRIVATE)
+  public long configureForTextureLayerComposition(
       @NonNull PlatformView platformView,
       @NonNull PlatformViewsChannel.PlatformViewCreationRequest request) {
     // This mode attaches the view to the Android view hierarchy and record its drawing

shell/platform/android/test/io/flutter/plugin/platform/PlatformViewsControllerTest.java

@@ -39,6 +39,7 @@
 import io.flutter.embedding.engine.systemchannels.AccessibilityChannel;
 import io.flutter.embedding.engine.systemchannels.MouseCursorChannel;
 import io.flutter.embedding.engine.systemchannels.PlatformViewsChannel;
+import io.flutter.embedding.engine.systemchannels.PlatformViewsChannel.PlatformViewTouch;
 import io.flutter.embedding.engine.systemchannels.SettingsChannel;
 import io.flutter.embedding.engine.systemchannels.TextInputChannel;
 import io.flutter.plugin.common.MethodCall;
@@ -79,6 +80,8 @@ public CountingPlatformView(Context context) {
 
     @Override
     public void dispose() {
+      // We have been removed from the view hierarhy before the call to dispose.
+      assertNull(view.getParent());
       disposeCalls++;
     }
 
@@ -98,6 +101,46 @@ public void onFlutterViewDetached() {
     }
   }
 
+  @Test
+  @Config(shadows = {ShadowFlutterJNI.class, ShadowPlatformTaskQueue.class})
+  public void itRemovesPlatformViewBeforeDiposeIsCalled() {
+    PlatformViewsController platformViewsController = new PlatformViewsController();
+    FlutterJNI jni = new FlutterJNI();
+    attach(jni, platformViewsController);
+    // Get the platform view registry.
+    PlatformViewRegistry registry = platformViewsController.getRegistry();
+
+    // Register a factory for our platform view.
+    registry.registerViewFactory(
+        CountingPlatformView.VIEW_TYPE_ID,
+        new PlatformViewFactory(StandardMessageCodec.INSTANCE) {
+          @Override
+          public PlatformView create(Context context, int viewId, Object args) {
+            return new CountingPlatformView(context);
+          }
+        });
+
+    // Create the platform view.
+    int viewId = 0;
+    final PlatformViewsChannel.PlatformViewCreationRequest request =
+        new PlatformViewsChannel.PlatformViewCreationRequest(
+            viewId,
+            CountingPlatformView.VIEW_TYPE_ID,
+            0,
+            0,
+            128,
+            128,
+            View.LAYOUT_DIRECTION_LTR,
+            null);
+    PlatformView pView = platformViewsController.createPlatformView(request, true);
+    assertTrue(pView instanceof CountingPlatformView);
+    CountingPlatformView cpv = (CountingPlatformView) pView;
+    platformViewsController.configureForTextureLayerComposition(pView, request);
+    assertEquals(0, cpv.disposeCalls);
+    platformViewsController.disposePlatformView(viewId);
+    assertEquals(1, cpv.disposeCalls);
+  }
+
   @Test
   @Config(shadows = {ShadowFlutterJNI.class, ShadowPlatformTaskQueue.class})
   public void itNotifiesPlatformViewsOfEngineAttachmentAndDetachment() {
@@ -121,7 +164,7 @@ public PlatformView create(Context context, int viewId, Object args) {
     int viewId = 0;
     final PlatformViewsChannel.PlatformViewCreationRequest request =
         new PlatformViewsChannel.PlatformViewCreationRequest(
-            viewId++,
+            viewId,
             CountingPlatformView.VIEW_TYPE_ID,
             0,
             0,