[REG 5.10 -> 5.11] Opening link with invalid scheme opens "chromewebdata" page (and reloads it infinitely)

On the current dev branch (with 5.10 merged), opening an invalid link such as what://:: in this test file opens a data:text/html,chromewebdata URL (search for kUnreachableWebDataURL in the Chromium sources for context).

On 5.9, the link is passed to acceptNavigationRequest (it isn't with dev it seems), and nothing is opened.