bug: OAuth Cordova plugin crashes on android due to missing getEngine implementation

[HarelM]

Bug Report

Capacitor Version

💊   Capacitor Doctor  💊 

Latest Dependencies:

  @capacitor/cli: 4.0.1
  @capacitor/core: 4.0.1
  @capacitor/android: 4.0.1
  @capacitor/ios: 4.0.1

Installed Dependencies:

  @capacitor/cli: 3.6.0
  @capacitor/core: 3.6.0
  @capacitor/android: 3.6.0
  @capacitor/ios: 3.6.0

[success] iOS looking great! 👌
[success] Android looking great! 👌

Platform(s)

Affects only android as far as I know

Current Behavior

When a plugin would like to evaluate a js code and run it in the webview this will crash android app in capacitor.

Expected Behavior

Cordova plugin should work without crashes, or there should be an equivalent plugin I could use

Code Reproduction

Basically use a cordova plugin with the following line in android:
this.webView.getEngine().evaluateJavascript("window.dispatchEvent(new MessageEvent('message', { data: 'data' }));", null);
This code can be found here:
https://github.com/AyogoHealth/cordova-plugin-oauth/blob/a09b837cefb1f17628eef1d6d8dba88877149383/src/android/OAuthPlugin.java#L124

Other Technical Details

npm --version output: 8.1.2

node --version output: v16.13.2

pod --version output (iOS issues only): 1.11.3

Additional Context

I can see the the mock codorva webview implementation returns null when one request the engine in order to evaluate js code.
I guess one could only implement this method at this point in time in order to allow plugins to be able to evaluate js when they run in capacitor environment.
See here:

capacitor/android/capacitor/src/main/java/com/getcapacitor/cordova/MockCordovaWebViewImpl.java

Line 241 in d744cbb

public CordovaWebViewEngine getEngine() {

Let me know if this is something that you would like to add to the mock and I might be able to send a PR.

[jcesarmobile]

This is a duplicate of #5390
It says webView.engine because that particular plugin uses kotlin, but the problem is the same.

As workaround if the plugin is yours or you want to fork it, the code can be changed to something like:

WebView webViewImpl;
if(this.webView.getEngine() != null){
    webViewImpl = ((WebView) this.webView.getEngine().getView());
}
else {
    webViewImpl = (WebView) this.webView.getView();
}
webViewImpl.evaluateJavascript("window.dispatchEvent(new MessageEvent('message', { data: 'data' }));", null);

[ionitron-bot]

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