Fail gracefully if profile Temp dir can not be accessed.

base/file_util_win.cc

-// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// Copyright (c) 2011 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/file_util.h"
 
 #include <windows.h>
 #include <propvarutil.h>
 #include <psapi.h>
 #include <shellapi.h>
 #include <shlobj.h>
@@ skipping 648 matching lines @@
     return false;
   }
   if (!CreateDirectory(parent_path)) {
     DLOG(WARNING) << "Failed to create one of the parent directories.";
     return false;
   }
 
   if (!::CreateDirectory(full_path_str, NULL)) {
     DWORD error_code = ::GetLastError();
     if (error_code == ERROR_ALREADY_EXISTS && DirectoryExists(full_path)) {
-      // This error code doesn't indicate whether we were racing with someone
-      // creating the same directory, or a file with the same path, therefore
-      // we check.
+      // This error code ERROR_ALREADY_EXISTS doesn't indicate whether we
+      // were racing with someone creating the same directory, or a file
+      // with the same path.  If DirectoryExists() returns true, we lost the
+      // race to create the same directory.
       return true;
     } else {
       LOG(WARNING) << "Failed to create directory " << full_path_str
                    << ", last error is " << error_code << ".";
       return false;
     }
   } else {
     return true;
   }
 }
@@ skipping 435 matching lines @@
       uint8 unused = *(touch + offset);
       offset += step_size;
     }
     FreeLibrary(dll_module);
   }
 
   return true;
 }
 
 }  // namespace file_util