round subpixels up to next integer in measureText

A common source of layout bugs we're seeing these days involves the
output of measureText() being fed into StaticLayout's constructor.
measureText() returns subpixel-accurate values, but StaticLayout only
takes integral bounds, resulting in the subpixel portion of the
bounds being truncated. This leaves StaticLayout with insufficient
space to layout the text that was just measured, causing all manner
of unexpected line breaks.

This could be causing issues elsewhere, as well. Until our text
pipeline is fully subpixel-perfect, it's best that measureText
guarantee that the value it returns will be sufficient to contain
the text, even if cast to int.

Bug: 8164205
Change-Id: Ib84947f0d0a1229287f5b19b99e7efd40f5317f7