fix(DefaultUIController): guard SSL-error dialog against finishing activity (#1065)

Resolves #1065

The crash reported in #1065 is a WindowManager$BadTokenException raised
from DefaultUIController.onShowSslCertificateErrorDialog when AlertDialog
is shown after the hosting Activity has already started its
finishing/destroyed teardown. The WebView delivers SSL error callbacks
on the main thread and there is no guarantee the cached mActivity is
still in a state where it can host a dialog.

This change short-circuits the path when the activity is null, finishing,
or destroyed, calling handler.cancel() in that case so we fail safe
rather than crash. The same check is repeated immediately before
AlertDialog.show(), and the show() call itself is wrapped in a try/catch
for the residual race where the activity transitions between our last
check and the platform call.

Author: jim-daf

agentweb-core/src/main/java/com/just/agentweb/DefaultUIController.java

@@ -367,6 +367,15 @@ public void onPermissionsDeny(String[] permissions, String permissionType, Strin
 
 	@Override
 	public void onShowSslCertificateErrorDialog(final WebView view, final SslErrorHandler handler, final SslError error) {
+		// Issue #1065: Activity may already be finishing/destroyed by the time the
+		// WebView delivers the SSL error callback on the main thread. Showing a
+		// dialog against a stale window token throws WindowManager$BadTokenException.
+		// Fail safe by cancelling the request when we cannot present UI.
+		if (mActivity == null || mActivity.isFinishing()
+				|| (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR1 && mActivity.isDestroyed())) {
+			handler.cancel();
+			return;
+		}
 		AlertDialog.Builder alertDialog = new AlertDialog.Builder(mActivity);
 		String sslErrorMessage;
 		switch (error.getPrimaryError()) {
@@ -402,7 +411,18 @@ public void onClick(DialogInterface dialog, int which) {
 				handler.cancel();
 			}
 		});
-		alertDialog.show();
+		// Re-check just before show in case the activity transitioned during string lookup.
+		if (mActivity.isFinishing()
+				|| (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR1 && mActivity.isDestroyed())) {
+			handler.cancel();
+			return;
+		}
+		try {
+			alertDialog.show();
+		} catch (android.view.WindowManager.BadTokenException | IllegalStateException e) {
+			// Activity window went away between our check and show(); fail safe.
+			handler.cancel();
+		}
 
 
 	}