Revert of Implement "Look Up In Dictionary" context menu item asynchronously.

Revert of Implement "Look Up In Dictionary" context menu item asynchronously. (patchset #6 id:100001 of https://codereview.chromium.org/1313553006/ )

Reason for revert:
Caused regression crbug.com/528929.

Original issue's description:
> Implement "Look Up In Dictionary" context menu item asynchronously. (OS X)
>
> Reduces the number of callers of the synchronous IPC in
> TextInputClientMac::GetAttributedSubstringFromRange() (so that eventually we can
> remove it).
>
> BUG=121917
> TEST=Verified "Look Up in Dictionary" by context menu feature works well.
>
> Committed: https://crrev.com/cabb6815f85f0e6297a55eb313a8e11373e2da9e
> Cr-Commit-Position: refs/heads/master@{#347306}

TBR=asvitkine@chromium.org,palmer@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=121917
Committed: https://crrev.com/a689467ce5c0d4f7f396a40509d40a557533aa0e
Cr-Commit-Position: refs/heads/master@{#347649}

[Shu Chen, 2015-09-08 00:51:11]

Created Revert of Implement "Look Up In Dictionary" context menu item
asynchronously.

[commit-bot: I haz the power, 2015-09-08 00:51:24]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1306713007/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1306713007/1

[commit-bot: I haz the power, 2015-09-08 00:51:48]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-09-08 00:52:26]

Patchset 1 (id:??) landed as
https://crrev.com/a689467ce5c0d4f7f396a40509d40a557533aa0e
Cr-Commit-Position: refs/heads/master@{#347649}