Correct and simplify direction setting for propertyedittool

Get the direction from CSS rather than HTML, to make sure
that it's defined and explicit rather than 'auto'.

Since 'direction' is always expected to be defined, there's
no reason to have the undefined test.

Currently, the <input> gets dir='auto', which doesn't actually
do the right thing in browsers.

Change-Id: I80b9ab02840617931b9070d101e324c5a01cd70f
Merge "Correct and simplify direction setting for propertyedittool"