[inspired by bug 702866]
Prerequisite: have an input string which, when typed in the omnibox, will show an associated keyword on the first suggestion (i.e., within the omnibox) (with or without an inline autocompletion) and one on a row other than the first one.]

Steps:
(1) Type this input.
(2) Tab to the lower row with the associated keyword.  (This means going into associated keyword mode on the top result, then leaving it and going lower in the dropdown.  Using the arrows to select the lower row does not cause this bug to reproduce.)
(3) If you now hit <esc>, you'll reset your tabbing and be back on the first result.  However, the omnibox text you type will be removed.

For example, with my profile, I can type "cr", which is associated with an omnibox extension named "cr".  Lower in the dropdown, I see a suggestion for crbug.com, which also has an associated keyword.  If tab down to and select that row, then hit esc, I'm left with a blank omnibox.

Similarly, I can type "c", which gives me an inline autocompletion to cs.chromium.org, which has an associated keyword.  Lower in the dropdown I again see the suggestion for crbug.com.  If I tab to it, then press escape, I see s.chromium.org in the omnibox, with ".chromium.org" being selected.  I think the omnibox remembered "the cursor position is after the first character; everything else should be selected", just forgot to restore the character that I typed ("c") so mis-computed what the first character was.