Pressing tab when auto-complete is up should cycle through the results

[bsclifton]

Test plan

#8824 (comment)

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• Did you search for similar issues before submitting this one?
  Yes

• Describe the issue you encountered:
  When you have auto-complete options enabled (history, bookmarks, popular sites, etc) you'll get results shown which match what you're typing in the URL bar. You can use arrow keys (up, down) to go through each entry. If you hit enter to choose one, it chooses it and immediately loads the URL.

However, when tab is pressed, it populates the rest of the URL with the entry you were on. It also shifts focus to the next element (URL bar loses focus). Even though the URL bar shows a full URL, it's not updating internal React state. If you click on the URL bar again and hit enter, it'll submit only what was partially typed

• Platform (Win7, 8, 10? macOS? Linux distro?):
  macOS

• Brave Version (revision SHA):
  0.15.304

• Steps to reproduce:

  1. Visit GitHub.com and load several pages, to build a history
  2. In the URL bar, type githu
  3. Notice the suggestions come up. Press arrow key down so that the result is highlighted
  4. Push TAB
  5. Notice that the URL bar fills itself up with what was highlighted and that focus is no longer in the URL bar
  6. Click inside the URL bar, to give it focus again
  7. Hit enter
  8. Notice that a search is done for githu

• Actual result:
  pushing tab looks like it is selecting a result (but it's not)

• Expected result:
  Tab (and shift+tab) is supposed to cycle the results, similar to arrow key up/down. This matches the behavior in Chrome (and other browsers)

• Will the steps above reproduce in a fresh profile? If not what other info can be added?
  Yes

• Is this an issue in the currently released version?

• Can this issue be consistently reproduced?

• Extra QA steps:
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• Screenshot if needed:

• Any related issues: