Turn on file access checks on Win.

base/win_util.cc

 // Copyright (c) 2010 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 "base/win_util.h"
 
 #include <aclapi.h>
 #include <shobjidl.h>  // Must be before propkey.
 #include <propkey.h>
 #include <propvarutil.h>
 #include <sddl.h>
 #include <shlobj.h>
 
 #include "base/logging.h"
 #include "base/win/registry.h"
 #include "base/scoped_handle.h"
 #include "base/scoped_ptr.h"
 #include "base/string_util.h"
 #include "base/stringprintf.h"
+#include "base/thread_restrictions.h"
 #include "base/win/windows_version.h"
 
 namespace win_util {
 
 #define SIZEOF_STRUCT_WITH_SPECIFIED_LAST_MEMBER(struct_name, member) \
     offsetof(struct_name, member) + \
     (sizeof static_cast<struct_name*>(NULL)->member)
 #define NONCLIENTMETRICS_SIZE_PRE_VISTA \
     SIZEOF_STRUCT_WITH_SPECIFIED_LAST_MEMBER(NONCLIENTMETRICS, lfMessageFont)
 
@@ skipping 90 matching lines @@
     if (size_ret < (buffer_size - 1)) {
       output.resize(size_ret);
       return output;
     }
     buffer_size *= 2;
   }
   return std::wstring();  // error
 }
 
 bool UserAccountControlIsEnabled() {
+  // This can be slow if Windows ends up going to disk.  Should watch this key
+  // for changes and only read it once, preferably on the file thread.
+  //   http://code.google.com/p/chromium/issues/detail?id=61644
+  base::ThreadRestrictions::ScopedAllowIO allow_io;
+
   base::win::RegKey key(HKEY_LOCAL_MACHINE,
       L"SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Policies\\System",
       KEY_READ);
   DWORD uac_enabled;
   if (!key.ReadValueDW(L"EnableLUA", &uac_enabled))
     return true;
   // Users can set the EnableLUA value to something arbitrary, like 2, which
   // Vista will treat as UAC enabled, so we make sure it is not set to 0.
   return (uac_enabled != 0);
 }
@@ skipping 72 matching lines @@
 
 #ifndef COPY_FILE_COPY_SYMLINK
 #error You must install the Windows 2008 or Vista Software Development Kit and \
 set it as your default include path to build this library. You can grab it by \
 searching for "download windows sdk 2008" in your favorite web search engine.  \
 Also make sure you register the SDK with Visual Studio, by selecting \
 "Integrate Windows SDK with Visual Studio 2005" from the Windows SDK \
 menu (see Start - All Programs - Microsoft Windows SDK - \
 Visual Studio Registration).
 #endif