Fix Windows build warning

Fix Windows build warning

When building midi_manager_winrt.cc, following warning is raised:
warning C4467: usage of ATL attributes is deprecated.

Attributed ATL code has been deprecated. New code style can be found in
https://msdn.microsoft.com/en-us/library/mt723604.aspx.

BUG=512433
Committed: https://crrev.com/5c8d5551030136f5acb4a10dde621f4edf724c6f
Cr-Commit-Position: refs/heads/master@{#416416}

[qiankun, 2016-09-02 17:33:00]

qiankun.miao@intel.com changed reviewers:
+ shaochuan@chromium.org, toyoshim@chromium.org

[qiankun, 2016-09-02 17:33:01]

PTAL.

[Takashi Toyoshima, 2016-09-02 17:59:19]

lgtm (assuming first bot failures were infra issues)

[qiankun, 2016-09-02 22:48:12]

The CQ bit was checked by qiankun.miao@intel.com to run a CQ dry run

[commit-bot: I haz the power, 2016-09-02 22:48:44]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-09-03 00:28:38]

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

[commit-bot: I haz the power, 2016-09-03 00:28:39]

Dry run: This issue passed the CQ dry run.

[qiankun, 2016-09-03 00:39:02]

The CQ bit was checked by qiankun.miao@intel.com

[commit-bot: I haz the power, 2016-09-03 00:39:28]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-09-03 00:44:27]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-09-03 00:46:51]

Description was changed from

==========
Fix Windows build warning

When building midi_manager_winrt.cc, following warning is raised:
warning C4467: usage of ATL attributes is deprecated.

Attributed ATL code has been deprecated. New code style can be found in
https://msdn.microsoft.com/en-us/library/mt723604.aspx.

BUG=512433
==========

to

==========
Fix Windows build warning

When building midi_manager_winrt.cc, following warning is raised:
warning C4467: usage of ATL attributes is deprecated.

Attributed ATL code has been deprecated. New code style can be found in
https://msdn.microsoft.com/en-us/library/mt723604.aspx.

BUG=512433

Committed: https://crrev.com/5c8d5551030136f5acb4a10dde621f4edf724c6f
Cr-Commit-Position: refs/heads/master@{#416416}
==========

[commit-bot: I haz the power, 2016-09-03 00:46:52]

Patchset 1 (id:??) landed as
https://crrev.com/5c8d5551030136f5acb4a10dde621f4edf724c6f
Cr-Commit-Position: refs/heads/master@{#416416}