Port some things in browser/{download,history}, minor things in common....

chrome/browser/download/download_exe.h

Index: chrome/browser/download/download_exe.h
===================================================================
--- chrome/browser/download/download_exe.h	(revision 0)
+++ chrome/browser/download/download_exe.h	(revision 0)
@@ -0,0 +1,18 @@
+// Copyright (c) 2008 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.
+
+#ifndef CHROME_BROWSER_DOWNLOAD_DOWNLOAD_EXE_H_
+#define CHROME_BROWSER_DOWNLOAD_DOWNLOAD_EXE_H_
+
+#include <set>
+#include <string>
+
+namespace download_util {
+
+// Copy all executable file extensions.
+void InitializeExeTypes(std::set<std::wstring>* exe_extensions);
+
+}  // namespace download_util
+
+#endif  // CHROME_BROWSER_DOWNLOAD_DOWNLOAD_EXE_H_