[webview_flutter_android] Copies Android implementation of webview_flutter from v4_webview (flutter#6851)

* new android release

* Version bump

* update all plugins config

* fix lints and add action item to changelog

Author: bparrishMines

packages/webview_flutter/webview_flutter_android/CHANGELOG.md

@@ -1,3 +1,9 @@
+## 3.0.0
+
+* **BREAKING CHANGE** Updates platform implementation to `2.0.0` release of
+  `webview_flutter_platform_interface`. See
+  [webview_flutter](https://pub.dev/packages/webview_flutter/versions/4.0.0) for updated usage.
+
 ## 2.10.4
 
 * Updates code for `no_leading_underscores_for_local_identifiers` lint.

packages/webview_flutter/webview_flutter_android/android/src/main/java/io/flutter/plugins/webviewflutter/DownloadListenerFlutterApiImpl.java

@@ -47,20 +47,6 @@ public void onDownloadStart(
         callback);
   }
 
-  /**
-   * Communicates to Dart that the reference to a {@link DownloadListener} was removed.
-   *
-   * @param downloadListener the instance whose reference will be removed
-   * @param callback reply callback with return value from Dart
-   */
-  public void dispose(DownloadListener downloadListener, Reply<Void> callback) {
-    if (instanceManager.containsInstance(downloadListener)) {
-      dispose(getIdentifierForListener(downloadListener), callback);
-    } else {
-      callback.reply(null);
-    }
-  }
-
   private long getIdentifierForListener(DownloadListener listener) {
     final Long identifier = instanceManager.getIdentifierForStrongReference(listener);
     if (identifier == null) {

packages/webview_flutter/webview_flutter_android/android/src/main/java/io/flutter/plugins/webviewflutter/DownloadListenerHostApiImpl.java

@@ -6,7 +6,6 @@
 
 import android.webkit.DownloadListener;
 import androidx.annotation.NonNull;
-import androidx.annotation.Nullable;
 import io.flutter.plugins.webviewflutter.GeneratedAndroidWebView.DownloadListenerHostApi;
 
 /**
@@ -21,11 +20,9 @@ public class DownloadListenerHostApiImpl implements DownloadListenerHostApi {
 
   /**
    * Implementation of {@link DownloadListener} that passes arguments of callback methods to Dart.
-   *
-   * <p>No messages are sent to Dart after {@link DownloadListenerImpl#release} is called.
    */
-  public static class DownloadListenerImpl implements DownloadListener, Releasable {
-    @Nullable private DownloadListenerFlutterApiImpl flutterApi;
+  public static class DownloadListenerImpl implements DownloadListener {
+    private final DownloadListenerFlutterApiImpl flutterApi;
 
     /**
      * Creates a {@link DownloadListenerImpl} that passes arguments of callbacks methods to Dart.
@@ -43,18 +40,8 @@ public void onDownloadStart(
         String contentDisposition,
         String mimetype,
         long contentLength) {
-      if (flutterApi != null) {
-        flutterApi.onDownloadStart(
-            this, url, userAgent, contentDisposition, mimetype, contentLength, reply -> {});
-      }
-    }
-
-    @Override
-    public void release() {
-      if (flutterApi != null) {
-        flutterApi.dispose(this, reply -> {});
-      }
-      flutterApi = null;
+      flutterApi.onDownloadStart(
+          this, url, userAgent, contentDisposition, mimetype, contentLength, reply -> {});
     }
   }