We're working on providing a way to pass thru Chromium commands as part of your Crosswalk build. Unfortunately, I do not know when that feature will be available, it requires some modifications of our build system to make it happen, its not something that we can just enable.
BTW -- one way to deal with removing the "width=device-width" for the Crosswalk build but keeping it in place for other devices (such as an iPad) is to try and insert the meta tag during initialization, I've seen this done, you might have to search for an example, I don't have one handy at this moment. Another way is to change that line in your index.html file to fit what works for Crosswalk and what works for iOS before each build. I realize that is a messy solution, but until we can provide the command-line features it is a work around.
