Revert of Revert of [AiS] Merge answers into highest-scoring result

Revert of Revert of [AiS] Merge answers into highest-scoring result (patchset #1 id:1 of https://codereview.chromium.org/598253002/)

Reason for revert:
Broken GN build:
http://build.chromium.org/p/chromium.linux/builders/Linux%20GN%20%28dbg%29/builds/13101

Original issue's description:
> Revert of [AiS] Merge answers into highest-scoring result (patchset #6 id:100001 of https://codereview.chromium.org/584653004/)
>
> Reason for revert:
> The new tests are flaky:
> http://build.chromium.org/p/chromium.memory/builders/Linux%20ASan%20LSan%20Tests%20%283%29/builds/7944
>
> Original issue's description:
> > [AiS] Merge answers into highest-scoring result
> >
> > Answer contents and type must always be copied to the highest-scoring
> > suggestion, to ensure answers are not lost due to suggestion
> > deduplication.
> >
> > BUG=415836
> > R=mpearson
> >
> > Committed: https://crrev.com/978a4bf4a3be714950ed265660bd9566f7abd922
> > Cr-Commit-Position: refs/heads/master@{#296520}
>
> TBR=mpearson@google.com,mpearson@chromium.org,newt@chromium.org,groby@chromium.org
> NOTREECHECKS=true
> NOTRY=true
> BUG=415836
>
> Committed: https://crrev.com/ba5d32190d4f056b11738b050b94895b655c52f7
> Cr-Commit-Position: refs/heads/master@{#296555}

TBR=mpearson@google.com,mpearson@chromium.org,newt@chromium.org,groby@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=415836
Committed: https://crrev.com/bffe11cb0e62af7c8d11b0c89b528b5f6f619e55
Cr-Commit-Position: refs/heads/master@{#296573}

[jiayl, 2014-09-24 23:22:03]

Created Revert of Revert of [AiS] Merge answers into highest-scoring result

[commit-bot: I haz the power, 2014-09-24 23:30:56]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/599273002/1

[jiayl, 2014-09-24 23:43:10]

The CQ bit was unchecked by jiayl@chromium.org

[commit-bot: I haz the power, 2014-09-24 23:43:20]

The CQ bit was unchecked by commit-bot@chromium.org

[jiayl, 2014-09-24 23:43:41]

The CQ bit was checked by jiayl@chromium.org

[commit-bot: I haz the power, 2014-09-24 23:43:58]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/599273002/1

[commit-bot: I haz the power, 2014-09-24 23:45:42]

Committed patchset #1 (id:1) as 120aea8257c1e485df62d5d4d75059d2674f145c

[commit-bot: I haz the power, 2014-09-24 23:47:24]

Patchset 1 (id:??) landed as
https://crrev.com/bffe11cb0e62af7c8d11b0c89b528b5f6f619e55
Cr-Commit-Position: refs/heads/master@{#296573}