The URL path/query in the omnibox are grey 600 on grey 100, which has a contrast ratio of 3.3, which is below the WCAG minimum.  When the omnibox is being edited, it is against white and thus has a ratio of 3.68, which is still below the minimum.  I think we need to fix this.

If we went to grey 700, that would be a contrast ratio of 5.43 in the steady state.  If we did some sort of custom grey, say a "grey 635" that linearly interpolated 35% of the way from 600 to 700 (#6b6f74), that would be a ratio of 4.54.

The current contrast of path against the hostname (which is grey 900) is 4.37.  If we went to grey 700, it would reduce the contrast with the hostname to 2.66.  If we used grey 635, it would have a contrast ratio of 3.18.

One other change we could do if we want the host to contrast more with the path is to use true black for the hostname.  That brings the contrast ratio with grey 635 up to 4.15, which is reasonably similar to how much it contrasts today.  (You know, if we're bending the Material Refresh rules anyway...)