Update RNCWebViewManager.java

Clarify comments and add warning on blocked subresource

android/src/main/java/com/reactnativecommunity/webview/RNCWebViewManager.java

@@ -17,6 +17,7 @@ import android.os.Environment;
 import androidx.annotation.RequiresApi;
 import androidx.core.content.ContextCompat;
 import android.text.TextUtils;
+import android.util.Log;
 import android.view.Gravity;
 import android.view.View;
 import android.view.ViewGroup;
@@ -801,8 +802,9 @@ public class RNCWebViewManager extends SimpleViewManager<WebView> {
 
     @Override
     public void onReceivedSslError(final WebView webView, final SslErrorHandler handler, final SslError error) {
+        // onReceivedSslError is called for most requests, per Android docs: https://developer.android.com/reference/android/webkit/WebViewClient#onReceivedSslError(android.webkit.WebView,%2520android.webkit.SslErrorHandler,%2520android.net.http.SslError)
         // WebView.getUrl() will return the top-level window URL.
-        // If a top-level navigation triggers this error handler, the top-level URL will be the failing URL (not the current URL).
+        // If a top-level navigation triggers this error handler, the top-level URL will be the failing URL (not the URL of the currently-rendered page).
         // This is desired behavior. We later use these values to determine whether the request is a top-level navigation or a subresource request.
         String topWindowUrl = webView.getUrl();
         String failingUrl = error.getUrl();
@@ -814,6 +816,7 @@ public class RNCWebViewManager extends SimpleViewManager<WebView> {
 
         if (!topWindowUrl.equalsIgnoreCase(failingUrl)) {
           // If error is not due to top-level navigation, then do not call onReceivedError()
+          Log.w("RNCWebViewManager", "Resource blocked from loading due to SSL error. Blocked URL: "+failingUrl);
           return;
         }