Added impersonation of the anonymous token around CloseClipboard

remoting/host/clipboard_win.cc

Index: remoting/host/clipboard_win.cc
diff --git a/remoting/host/clipboard_win.cc b/remoting/host/clipboard_win.cc
index 21ae6c77395d1e26c030260cd0eab96e72cc6530..bc062e7aadbc35e521334709b44bb1bf5d8129a0 100644
--- a/remoting/host/clipboard_win.cc
+++ b/remoting/host/clipboard_win.cc
@@ -32,7 +32,9 @@ class ScopedClipboard {
 
   ~ScopedClipboard() {
     if (opened_) {
+      ::ImpersonateAnonymousToken(GetCurrentThread());

[jschuh, 2014/12/11 17:53:06]

I know the impersonate *shouldn't* fail, but it's best to catch it regardless.
So, something like:

  BOOL shouldRevert = ::ImpersonateAnonymousToken(GetCurrentThread());
  DCHECK(shouldRevert);
  ::CloseClipboard();
  if (shouldRevert)
    ::RevertToSelf();

[dcheng, 2014/12/11 18:18:23]

Can we use a scoper to wrap this logic?
... also, unrelated but... what is this API even used for?

       ::CloseClipboard();
+      ::RevertToSelf();
     }
   }