Introduce bypass logic for SetCursorLocation message.

Introduce bypass logic for SetCursorLocation message. 

This CL is second try of https://codereview.chromium.org/12017010/

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=178543

[Seigo Nonaka, 2013-01-22 11:58:24]

Sorry previous patch breaks ui_unittests and close tree.
The reason for breakage is I forget fix ui_unittests after splitting CL.
I temporary disabled some test.
All disabled tests should be re-enabled once codereview.chromium.org/11956008 is
landed.

Thanks

[satorux1, 2013-01-22 17:24:59]

When you are relanding, please upload the original patch as Patch Set 1, then
upload the new version as Patch Set 2, so reviewers can see the diff.

[Seigo Nonaka, 2013-01-23 04:53:10]

Sorry for unclear review.
I uploaded base patch.
Please take an another look?

Thank you.

[satorux1, 2013-01-23 17:43:38]

LGTM

[commit-bot: I haz the power, 2013-01-24 03:48:40]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/nona@chromium.org/12039019/5002

[commit-bot: I haz the power, 2013-01-24 07:21:00]

Change committed as 178543