Comment 3 for bug 1534239

After discussion with Bill, James and Benjamin, the proposed solution is this:

 - short term fix for OTA 9.5: in narrow layout, when mouse is connected, the bottom edge hint turns into a bottom edge bar that is clickable, thus reducing the height of the webview

 - longer term fix (OTA 10 or later): in narrow layout, when mouse is connected, the bottom edge hint is hidden and a new button is added to the chrome (between the address bar and the drawer menu) to open the tabs view