Fix NullPointerException after taking a photo by a camera app on Andr…

…oid.

android/src/main/java/com/pichillilorenzo/flutter_inappwebview/InAppWebView/InAppWebViewChromeClient.java

@@ -72,7 +72,7 @@ public class InAppWebViewChromeClient extends WebChromeClient implements PluginR
   private static final int PICKER = 1;
   private static final int PICKER_LEGACY = 3;
   final String DEFAULT_MIME_TYPES = "*/*";
-  private Uri outputFileUri;
+  private static Uri outputFileUri;
 
   protected static final FrameLayout.LayoutParams FULLSCREEN_LAYOUT_PARAMS = new FrameLayout.LayoutParams(
           ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT, Gravity.CENTER);