Introduce bypass logic for SetCursorLocation message.

Introduce bypass logic for SetCursorLocation message.

Current Chrome does not emit SetCursorLocation message to ibus-daemon because both candidate window and input context is in same process. 
It was achieved by injecting IBusClient into ui::InputMethodIBus, but we are now able to bypass them only in chromeos/ directory. 
With this refactoring, we can remove ui::internal::IBusClient, IBusChromeOSClientImpl and their injection code. 

This patch introduces bypass code for SetCursorLocation, but not used yet.

BUG=None 
TEST=Manually done on lumpy.

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=177995

[Seigo Nonaka, 2013-01-21 04:48:30]

I split https://codereview.chromium.org/11956008/ into chromeos/ part and the
others.
This patch introduces bypass logic for SetCursorLocation but not used until
landing https://codereview.chromium.org/11956008/ .

[satorux1, 2013-01-22 07:10:04]

LGTM

[commit-bot: I haz the power, 2013-01-22 08:23:58]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/nona@chromium.org/12017010/1

[commit-bot: I haz the power, 2013-01-22 10:41:34]

Change committed as 177995