Call CloseClipboard() with anonymous access token.

Call CloseClipboard() with anonymous access token.

Windows API makes it possible to impersonate access token of the last
process that called CloseClipboard(). Chromoting calls it from a system
process, so it has to impersonate anonymous token before calling
CloseClipboard().

BUG=441834
Committed: https://crrev.com/60f87ce4c93659d34e5d996aada4288d3c793c7b
Cr-Commit-Position: refs/heads/master@{#308155}

[Sergey Ulanov, 2014-12-12 18:53:35]

sergeyu@chromium.org changed reviewers:
+ wez@chromium.org

[Wez, 2014-12-12 19:25:36]

lgtm

https://codereview.chromium.org/798943003/diff/20001/remoting/host/clipboard_...
File remoting/host/clipboard_win.cc (right):

https://codereview.chromium.org/798943003/diff/20001/remoting/host/clipboard_...
remoting/host/clipboard_win.cc:38: CHECK(result);
nit: I think it'd be acceptable to just CHECK(ApiCall()) in this case.

https://codereview.chromium.org/798943003/diff/20001/remoting/host/clipboard_...
remoting/host/clipboard_win.cc:40: ::RevertToSelf();
CHECK this as well?

[Sergey Ulanov, 2014-12-12 19:34:00]

https://codereview.chromium.org/798943003/diff/20001/remoting/host/clipboard_...
File remoting/host/clipboard_win.cc (right):

https://codereview.chromium.org/798943003/diff/20001/remoting/host/clipboard_...
remoting/host/clipboard_win.cc:38: CHECK(result);
On 2014/12/12 19:25:36, Wez wrote:
> nit: I think it'd be acceptable to just CHECK(ApiCall()) in this case.

Side effects inside DCHECKs are often hard to debug. It's not a problem for
CHECK, but still I think it's better to avoid this pattern, e.g. in case this
CHECK gets replaced with DCHECK.

https://codereview.chromium.org/798943003/diff/20001/remoting/host/clipboard_...
remoting/host/clipboard_win.cc:40: ::RevertToSelf();
On 2014/12/12 19:25:36, Wez wrote:
> CHECK this as well?

Done.

[Sergey Ulanov, 2014-12-12 19:36:55]

The CQ bit was checked by sergeyu@chromium.org

[commit-bot: I haz the power, 2014-12-12 19:38:16]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/798943003/40001

[commit-bot: I haz the power, 2014-12-12 20:47:37]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2014-12-12 20:48:18]

Patchset 3 (id:??) landed as
https://crrev.com/60f87ce4c93659d34e5d996aada4288d3c793c7b
Cr-Commit-Position: refs/heads/master@{#308155}