Write an error message to the debug log when the host is shutting down because of a policy setting.

remoting/host/curtain_mode_mac.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "remoting/host/curtain_mode.h"
 
 #include <ApplicationServices/ApplicationServices.h>
 #include <Carbon/Carbon.h>
 #include <Security/Security.h>
 #include <unistd.h>
@@ skipping 73 matching lines @@
   // TODO(jamiewalch): If the underlying OS bug is ever fixed, we should support
   // curtain mode on suitable versions of Lion.
   if (base::mac::IsOSLion()) {
     LOG(ERROR) << "Host curtaining is not supported on Mac OS X 10.7.";
     return false;
   }
 
   // Try to install the switch-in handler. Do this before switching out the
   // current session so that the console session is not affected if it fails.
   if (!InstallEventHandler()) {
+    LOG(ERROR) << "Failed to install the switch-in handler.";
     return false;
   }
 
   base::mac::ScopedCFTypeRef<CFDictionaryRef> session(
       CGSessionCopyCurrentDictionary());
 
   // CGSessionCopyCurrentDictionary has been observed to return NULL in some
   // cases. Once the system is in this state, curtain mode will fail as the
   // CGSession command thinks the session is not attached to the console. The
   // only known remedy is logout or reboot. Since we're not sure what causes
@@ skipping 61 matching lines @@
 
 // static
 scoped_ptr<CurtainMode> CurtainMode::Create(
     const base::Closure& on_session_activate,
     const base::Closure& on_error) {
   return scoped_ptr<CurtainMode>(
       new CurtainModeMac(on_session_activate, on_error));
 }
 
 }  // namespace remoting