Fatal error if InAppBrowser is close immediately

I have this error when the inAppBrowser is close soon enough ( for eg within 1 sec )

> `java.lang.NullPointerException: Attempt to invoke virtual method 'void org.apache.cordova.inappbrowser.InAppBrowserDialog.show()' on a null object reference`

I could solve the problem by adding a null check on line no. 282 on inAppBrowser.java as follows
replace `dialog.show();` with `if(dialog != null) dialog.show();`

[screenshot](http://prntscr.com/lti6lm)

I am not an expert on java android and so can someone confirm this fix or give a good way to fix the problem.

Thx

Start in inAppBrowser.java around line 282 and reproduce the reported case by closing the InAppBrowser within about one second. Trace whether dialog can be null at that point and verify that the chosen fix prevents the NullPointerException without breaking normal dialog display.

Written by the indexing model from the issue text.