Fix CascadingMenuPopup width on API 19 and below

Happens because CascadingMenuPopup calls setWidth() rather
than setContentWidth() like StandardMenuPopup does.
setContentWidth() takes into account any padding in the popup
background, which we use since the drawable is a 9-patch on
API <= 19.

BUG: 30365568
Change-Id: I2cfeb83e9dd33ac46ab9a445b4dcdf999c507ce7
1 file changed