Add Locking calls to file_io.h plus implementations and test

util/test/errors.h

 // Copyright 2014 The Crashpad Authors. All rights reserved.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //     http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
 #ifndef CRASHPAD_UTIL_TEST_ERRORS_H_
 #define CRASHPAD_UTIL_TEST_ERRORS_H_
 
 #include <string>
 
+#include "build/build_config.h"
+
 namespace crashpad {
 namespace test {
 
 // These functions format messages in a similar way to the PLOG and PCHECK
 // family of logging macros in base/logging.h. They exist to interoperate with
 // gtest assertions, which don’t interoperate with logging but can be streamed
 // to.
 //
 // Where non-test code could do:
 //   PCHECK(rv == 0) << "close";
@@ skipping 28 matching lines @@
 //! string that `strerror()` uses in these cases.
 //!
 //! \param[in] base A string to prepend to the error description.
 //!
 //! \return A string of the format `"Operation not permitted (1)"` if `errno`
 //!     has the value `EPERM` on a system where this is defined to be `1`. If
 //!     \a base is not empty, it will be prepended to this string, separated by
 //!     a colon.
 std::string ErrnoMessage(const std::string& base = std::string());
 
+#if defined(OS_WIN) || DOXYGEN
+//! \brief Formats an error message using `GetLastError()`.
+//!
+//! The returned string will combine the \a base string, if supplied, with a
+//! a textual and numeric description of the error. The format is the same as
+//! the `PLOG()` formatting in base.
+std::string ErrorMessage(const std::string& base = std::string());
+#endif
+
 }  // namespace test
 }  // namespace crashpad
 
 #endif  // CRASHPAD_UTIL_TEST_ERRORS_H_