[CleanUp] Add MoveMouseToInHost to aura::test::EventGenerator

Add MoveMouseToInHost to aura::test::EventGenerator
* remove local functions to move the mouse in host coordinates.
* updated tests that should use host coordinates instead of
  root.

BUG=none
TEST=covered by tests.

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=197651

[sky, 2013-04-30 23:06:37]

LGTM

[commit-bot: I haz the power, 2013-04-30 23:16:07]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/oshima@chromium.org/14293028/9001

[commit-bot: I haz the power, 2013-05-01 01:36:05]

Retried try job too often on linux_chromeos for step(s) cc_unittests
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=linux_chro...

[commit-bot: I haz the power, 2013-05-01 01:42:53]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/oshima@chromium.org/14293028/9001

[commit-bot: I haz the power, 2013-05-01 02:20:23]

Retried try job too often on linux_chromeos for step(s) cc_unittests
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=linux_chro...

[commit-bot: I haz the power, 2013-05-01 16:00:12]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/oshima@chromium.org/14293028/9001

[commit-bot: I haz the power, 2013-05-01 17:18:36]

Change committed as 197651