win: Add bootstrap[c].exe for sandbox integration (see #3824)

Replace cef_sandbox.lib usage with bootstrap executables.
See the SandboxSetup Wiki page for details.

libcef_dll/bootstrap/bootstrap_util_win.h

@@ -0,0 +1,51 @@
+// Copyright (c) 2025 The Chromium Embedded Framework 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 CEF_LIBCEF_DLL_BOOTSTRAP_BOOTSTRAP_UTIL_WIN_H_
+#define CEF_LIBCEF_DLL_BOOTSTRAP_BOOTSTRAP_UTIL_WIN_H_
+#pragma once
+
+#include <windows.h>
+
+#include <string>
+
+#include "base/files/file_path.h"
+
+namespace base {
+class CommandLine;
+}
+
+namespace bootstrap_util {
+
+namespace switches {
+inline constexpr char kModule[] = "module";
+}
+
+// Returns true if |name| is one of the default bootstrap executable names.
+bool IsDefaultExeName(const std::wstring& name);
+
+// Returns the command-line configured module value without validation.
+std::wstring GetModuleValue(const base::CommandLine& command_line);
+
+// The following functions can only be called in unsandboxed processes.
+
+// Returns the fully qualified file path for the executable module.
+base::FilePath GetExePath();
+
+// Returns the fully qualified file path for |module|.
+base::FilePath GetModulePath(HMODULE module);
+
+// Returns the command-line configured module value if it passes validation.
+std::wstring GetValidatedModuleValue(const base::CommandLine& command_line,
+                                     const base::FilePath& exe_path);
+
+// Returns the default module name (executable name without extension).
+std::wstring GetDefaultModuleValue(const base::FilePath& exe_path);
+
+// Returns true if loading |module| is allowed.
+bool IsModulePathAllowed(HMODULE module, const base::FilePath& exe_path);
+
+}  // namespace bootstrap_util
+
+#endif  // CEF_LIBCEF_DLL_BOOTSTRAP_BOOTSTRAP_UTIL_WIN_H_