Invalidate a slightly larger rect when updating popup annotations.
Invalidate a slightly larger rect when updating popup annotations.

It looks like sometimes there are rounding errors in the display
pipeline when displaying / hiding popup annotations. Compensate by
rouding up the damaged rect slightly.

BUG=chromium:662804

Review-Url: https://codereview.chromium.org/2492733002

DrAlexx/pdfium,DrAlexx/pdfium,DrAlexx/pdfium,DrAlexx/pdfium