Expose a function to get the path to a DLL.

chrome/installer/util/module_util_win.h

+// Copyright (c) 2015 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.
+
+// This file defines a utility function to get the full path of a module.
+
+#ifndef CHROME_INSTALLER_UTIL_MODULE_UTIL_WIN_H_
+#define CHROME_INSTALLER_UTIL_MODULE_UTIL_WIN_H_
+
+#include "base/files/file_path.h"
+#include "base/strings/string16.h"
+#include "base/strings/string_piece.h"
+
+namespace installer {
+
+// Returns the full path to a module named |module_name|, or an empty path if

[grt (UTC plus 2), 2015/10/30 19:33:14]

this is hard to document. :-) what do you think of:
// Returns the full path to |module_name|. Both dev builds (where |module_name|
// is in the current executable's directory) and proper installs (where
// |module_name| is in a versioned sub-directory of the current executable's
// directory) are suported. In the latter case, |version| is populated with the
// name of the versioned sub-directory (i.e., the current executable's
// version). Returns an empty path if the current executable appears to reside
// in a proper install but version information is missing. The identified file
// is not guaranteed to exist.

[fdoray, 2015/10/30 21:12:49]

Done.

+// the desired module is not in the directory of the current executable and
+// there is not version resource in the current module. On output, if the
+// desired module is not in the directory of the current executable, |version|
+// is populated with the version resource of the current module (if any).
+base::FilePath GetModulePath(const base::StringPiece16& module_name,
+                             base::string16* version);
+
+}  // namespace installer
+
+#endif  // CHROME_INSTALLER_UTIL_MODULE_UTIL_WIN_H_