feat: set background color to white for android webview

Author: zigbang-rad

src/android/InAppBrowser.java

@@ -1029,6 +1029,7 @@ public void onClick(View v) {
 
                 // WebView
                 inAppWebView = new WebView(cordova.getActivity());
+                inAppWebView.setBackgroundColor(Color.WHITE);
                 inAppWebView.setLayoutParams(new LinearLayout.LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT));
                 inAppWebView.setId(Integer.valueOf(6));
                 // File Chooser Implemented ChromeClient