PR 1.5.3: running the same 2 showNativeDialog(..., tag, prio) calls twice in test.html page succeeds on first exec, errors on second exec

[estory1]

Repro:

1) In your browser, at http://{device IP}:12345/test.html paste this code:

{
    "command": "execute_script",
    "script": "PurpleRobot.showNativeDialog('A', 'B', 'C', 'D', '', '', 'MA', 5); PurpleRobot.showNativeDialog('E', 'F', 'G', 'H', '', '', 'MA', 50);"
}

2) In your browser, run that script. Response:

{
  "command": "execute_script",
  "status": "ok"
}

3) On your device, hit the "G" button on the first prompt, then the "C" button on the second. 4) In your browser, hit the Back button (used Chrome in my testing). 5) In your browser, run the script again. Response:

{
  "message": "org.mozilla.javascript.WrappedException: Wrapped java.lang.NullPointerException",
  "command": "execute_script",
  "status": "error"
}

Expected behavior is that the response in step 2 would appear both times...

[estory1]

I suspect it's a content caching issue with the web server (Back button handling), because if you refresh the test.html page between steps 4 and 5, then the response from step 2 is displayed again.

[audaciouscode]

It was an unrelated race condition between the scripting engine and the dialog UI. Fixed.