Add TaskMemory, which can read another Mach task’s memory, and its test

util/test/errors.cc

+// 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.
+
+#include "util/test/errors.h"
+
+#include <errno.h>
+
+#include "base/safe_strerror_posix.h"
+#include "base/strings/stringprintf.h"
+
+namespace crashpad {
+namespace test {
+
+std::string ErrnoMessage(int err, const std::string& base) {
+  return base::StringPrintf("%s%s%s (%d)",
+                            base.c_str(),
+                            base.empty() ? "" : ": ",
+                            safe_strerror(errno).c_str(),
+                            err);
+}
+
+std::string ErrnoMessage(const std::string& base) {
+  return ErrnoMessage(errno, base);
+}
+
+}  // namespace test
+}  // namespace crashpad