GH-417: Handle non-default target attribute values (e.g. target=on links in WKWebView implementation on iOS (#418)

Author: dpa99c

src/ios/CDVWKInAppBrowser.m

@@ -573,7 +573,14 @@ - (void)webView:(WKWebView *)theWebView decidePolicyForNavigationAction:(WKNavig
     }
 
     if(shouldStart){
-        decisionHandler(WKNavigationActionPolicyAllow);
+        // Fix GH-417: Handle non-default target attribute
+        // Based on https://stackoverflow.com/a/25853806/777265
+        if (!navigationAction.targetFrame.isMainFrame){
+            [theWebView loadRequest:navigationAction.request];
+            decisionHandler(WKNavigationActionPolicyCancel);
+        }else{
+            decisionHandler(WKNavigationActionPolicyAllow);
+        }
     }else{
         decisionHandler(WKNavigationActionPolicyCancel);
     }