Match whole path components in DevicePathToDriveLetterPath(). Add tests.

base/win/win_api_interface.cc

Index: base/win/win_api_interface.cc
diff --git a/base/win/win_api_interface.cc b/base/win/win_api_interface.cc
new file mode 100644
index 0000000000000000000000000000000000000000..605d185d68eaea2b69da9c11443a0903aab80161
--- /dev/null
+++ b/base/win/win_api_interface.cc
@@ -0,0 +1,17 @@
+// Copyright (c) 2012 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/win_api_interface.h"
+
+#include "base/memory/singleton.h"
+
+namespace base {
+namespace win {
+
+WinApiInterface* WinApiInterface::GetInstance() {
+  return Singleton<WinApiInterface>::get();
+}
+
+}  // namespace win
+}  // namespace base