Fix a WebView longpress bug.

Longpressing on a WebView while the WebTextView is up calls
WebTextView::performLongPress().  This used to be fine, but now
we may still leave the WebTextView up while the user is longpressing
on something else.  Check to ensure that the focus is the same
as the cursor before calling WebTextView's version.  Also,
send a click if the user longpresses on a different WebTextView,
so it will now behave appropriately.  Requires a change in
external/webkit.

Also remove a duplicate check for inEditingMode().