[omnibox] Adjust table styling to accommodate cells with long content.

1) Set fixed but larger (4 lines + some added padding) row heights. Previously,
rows where 3 lines high, but grew on hover.
2) On hovering over a cell, vertical scroll bar is added only to that single
cell and not the other cells in the same row.
3) The 'additional info' column is multi-lined even when non-hovered (hence the
added padding to row height), which unfortunately also means it has no ellipses
to signify when it's elided.

Bug: 891303
Change-Id: I3d21424a80f477cc9fce835e1217d9d8e7b4b107
Reviewed-on: https://chromium-review.googlesource.com/c/1377183
Commit-Queue: manuk hovanesian <manukh@chromium.org>
Reviewed-by: Tommy Li <tommycli@chromium.org>
Cr-Commit-Position: refs/heads/master@{#617196}
1 file changed