Scenario: I have a bookmark to a page that no longer exists.

Problem: The bookmark will continue surfacing in the Omnibox. The bookmark can't be removed without opening chrome://bookmarks or finding the bookmark in whatever folder it's nested in -- visiting the page and clicking the omnibox star or hitting Ctrl+D doesn't work when the bookmarked URL immediately redirects elsewhere.

Suggestion: Feature to delete a bookmark from the omnibox, or at least open the bookmark dialog for that URL. Some ideas:
A. Keyboard shortcut to delete a history entry could trigger this dialog.
B. Clicking the star in the omnibox suggestion could trigger this dialog.
C. Detect dead bookmarks (visiting a bookmark that redirects to another page could trigger a prompt... although some bookmarks are useful precisely BECAUSE they redirect)

Of course, we shouldn't delete the bookmark immediately without confirmation (we could show an undo option of some kind instead of a dialog, but that's outside the scope of this FR).