certain flavor of prototype.js can break web message functionality

Description

Native - JS web messaging is broken on some sites utilizing prototype.js.

Version
SDK: 1.0.1418.22
Runtime: 107.0.1418.62
Framework: WPF
OS: Win10

Repro Steps

I ran into the issue while I was visiting our Jenkins site, but I managed to narrow down the issue and make it reproducible.

1. Get the Jenkins flavor of prototype.js

2. Inject the following code - make sure to do it before starting navigation:

    webView2.CoreWebView2.WebMessageReceived += WebMessageReceived;
    // Downloaded from: https://raw.githubusercontent.com/jenkinsci/jenkins/master/war/src/main/webapp/scripts/prototype.js
    var prototypeJS = File.ReadAllText(@"prototype.js");
    await webView2.CoreWebView2.AddScriptToExecuteOnDocumentCreatedAsync(prototypeJS);
    await webView2.CoreWebView2.AddScriptToExecuteOnDocumentCreatedAsync("window.chrome.webview.postMessage([{\"age\": 21}, {\"age\": 23}]);");
    
    private void WebMessageReceived(object? sender, CoreWebView2WebMessageReceivedEventArgs e)
    {
        var message = e.WebMessageAsJson;
        try
        {
            var info = System.Text.Json.JsonSerializer.Deserialize<Info[]>(message);
            Debug.WriteLine(info);
        }
        catch (Exception ex)
        {
            Debug.WriteLine(ex.Message);
        }
    }
   
    public class Info
    {
        [JsonPropertyName("age")]
        public int Age { get; set; } 
    }```
   
   

3. Start the browser - it won't be able to deserialize the web message

Notes:

• The issue can only be reproduced with arrays
• See the diff between the official prototype.js and Jenkins flavor of prototype.js.

E.g. see the change in the Array.prototype:

function toJSON() {
  var results = [];
  this.each(function(object) {
   var value = Object.toJSON(object);
   if (value !== undefined) results.push(value);
  });
  return '[' + results.join(', ') + ']';
 }

• This issue might happen with any sites overriding certain prototypes
• When prototype.js is injected into the page the e.WebMessageAsJson looks like this (BAD version):

"\"[{\\\"age\\\": 21}, {\\\"age\\\": 23}]\""

• When prototype.js is NOT injected into the page, e.WebMessageAsJson looks like this (GOOD version):

"[{\"age\":21},{\"age\":23}]"

AB#47984249