Create ScopedTempDir, implement it on POSIX, and use it where appropriate.

util/test/scoped_temp_dir.cc

Index: util/test/scoped_temp_dir.cc
diff --git a/util/test/scoped_temp_dir.cc b/util/test/scoped_temp_dir.cc
new file mode 100644
index 0000000000000000000000000000000000000000..a2f8d251430fde0adc2227365c539f34ab6d335d
--- /dev/null
+++ b/util/test/scoped_temp_dir.cc
@@ -0,0 +1,28 @@
+// Copyright 2015 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/scoped_temp_dir.h"
+
+namespace crashpad {
+namespace test {
+
+ScopedTempDir::ScopedTempDir() : path_(CreateTemporaryDirectory()) {
+}
+
+ScopedTempDir::~ScopedTempDir() {
+  RecursivelyDeleteTemporaryDirectory(path());
+}
+
+}  // namespace test
+}  // namespace crashpad