return key doesn’t validate the active form

This is a regression observed with the latest trunk (the last release, based on revision 501, doesn’t exhibit this behaviour).

Run the following simple QML scene with qmlscene:

    import QtQuick 2.0
    import com.canonical.Oxide 1.0
    WebView {
        width: 800
        height: 600
        url: "http://start.ubuntu.com"
    }

Focus the search box, enter any number of characters, then press the return key.

Expected result: the search is triggered and the results page starts loading
Current result: nothing happens

I can reliably reproduce the issue both on desktop (x86-64) with a physical keyboard and on a Nexus 7 with the OSK.