Fix HWNDMessageHandler::OnSetCursor handling of HTERROR.

Fix HWNDMessageHandler::OnSetCursor handling of HTERROR.

Handling HTERROR WM_SETCURSOR messages apparently causes a regression.
Modals don't pulse, beep, and come foreground when the parent is clicked.
This originally regressed with my http://crrev.com/188817.

BUG=375181
TEST=Clicking a browser with a window-modal dialog causes the dialog to pulse, beep, and the window pair to come foreground.
R=sky@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=272353

[msw, 2014-05-22 05:45:12]

Hey Scott, please take a look; I'm sorry this went unfixed for so long!

[sky, 2014-05-22 14:06:57]

LGTM

[msw, 2014-05-22 14:53:53]

The CQ bit was checked by msw@chromium.org

[commit-bot: I haz the power, 2014-05-22 14:55:28]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/msw@chromium.org/284313016/1

[commit-bot: I haz the power, 2014-05-22 15:29:26]

FYI, CQ is re-trying this CL (attempt #1).
Please consider checking whether the failures are real,
and report flakes to chrome-troopers@google.com.
The failing builders are:
  win_gpu_triggered_tests on tryserver.chromium.gpu
(http://build.chromium.org/p/tryserver.chromium.gpu/builders/win_gpu_triggered...)

[commit-bot: I haz the power, 2014-05-22 15:31:28]

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

[commit-bot: I haz the power, 2014-05-22 15:31:28]

Try jobs failed on following builders:
  win_gpu_triggered_tests on tryserver.chromium.gpu
(http://build.chromium.org/p/tryserver.chromium.gpu/builders/win_gpu_triggered...)

[msw, 2014-05-22 15:32:08]

The CQ bit was checked by msw@chromium.org

[commit-bot: I haz the power, 2014-05-22 15:33:42]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/msw@chromium.org/284313016/1

[commit-bot: I haz the power, 2014-05-22 15:37:32]

FYI, CQ is re-trying this CL (attempt #1).
Please consider checking whether the failures are real,
and report flakes to chrome-troopers@google.com.
The failing builders are:
  win_gpu_triggered_tests on tryserver.chromium.gpu
(http://build.chromium.org/p/tryserver.chromium.gpu/builders/win_gpu_triggered...)

[commit-bot: I haz the power, 2014-05-22 15:39:49]

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

[commit-bot: I haz the power, 2014-05-22 15:39:49]

Try jobs failed on following builders:
  win_gpu_triggered_tests on tryserver.chromium.gpu
(http://build.chromium.org/p/tryserver.chromium.gpu/builders/win_gpu_triggered...)

[msw, 2014-05-22 22:53:40]

The CQ bit was checked by msw@chromium.org

[commit-bot: I haz the power, 2014-05-22 22:54:55]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/msw@chromium.org/284313016/1

[commit-bot: I haz the power, 2014-05-22 22:57:07]

Change committed as 272353