update testing doc

Documentation/Contributors/TestingGuide/README.md

@@ -758,7 +758,7 @@ You can run or debug the tests by using the first two buttons.  The third button
 
 This runner has lots of options, such as only showing failing tests or automatically re-running the tests on a test interval (great for development when combined with `fdefineSuite`!).  You can hover over each of the buttons to see what they do.
 
-Instead of using Chrome or Firefox, the WebStorm configuration uses [Electron](https://github.com/atom/electron) as the browser, which runs V8 (Chrome) inside of a node process. We have configured it to run headless so that no browser window pops up while testing.  If you ever have a need to run a specific browser from within WebStorm, simply click the `Run tests` combo box and select `edit configuration`.  From there it's self-explanatory.'
+The WebStorm configuration uses Chrome Headless as the browser, which runs Chrome inside of a node process and no browser window pops up while testing.  If you ever have a need to run a specific browser from within WebStorm, simply click the `Run tests` combo box and select `edit configuration`.  From there it's self-explanatory.'
 
 To make jumping between the source and spec files easier download the  [Cesium WebStorm plugin](https://github.com/AnalyticalGraphicsInc/cesium-webstorm-plugin).