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.cc

@@ -0,0 +1,82 @@
+// 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.
+
+#include "cef/libcef_dll/bootstrap/bootstrap_util_win.h"
+
+#include "base/check_op.h"
+#include "base/command_line.h"
+
+namespace bootstrap_util {
+
+namespace {
+
+constexpr wchar_t kWindowsSelfName[] = TEXT("bootstrap");
+constexpr wchar_t kConsoleSelfName[] = TEXT("bootstrapc");
+
+// Returns the file name only without extension, if any.
+inline std::wstring NamePart(const base::FilePath& path) {
+  return path.BaseName().RemoveExtension().value();
+}
+
+}  // namespace
+
+bool IsDefaultExeName(const std::wstring& name) {
+  return base::FilePath::CompareEqualIgnoreCase(name, kWindowsSelfName) ||
+         base::FilePath::CompareEqualIgnoreCase(name, kConsoleSelfName);
+}
+
+std::wstring GetModuleValue(const base::CommandLine& command_line) {
+  if (command_line.HasSwitch(switches::kModule)) {
+    const auto& value = command_line.GetSwitchValuePath(switches::kModule);
+    if (!value.empty()) {
+      return NamePart(value);
+    }
+  }
+
+  return std::wstring();
+}
+
+base::FilePath GetExePath() {
+  HMODULE hModule = ::GetModuleHandle(nullptr);
+  CHECK(hModule);
+  return GetModulePath(hModule);
+}
+
+base::FilePath GetModulePath(HMODULE module) {
+  wchar_t buffer[MAX_PATH];
+  DWORD length = ::GetModuleFileName(module, buffer, MAX_PATH);
+  CHECK_NE(length, 0U);
+  CHECK_LT(length, static_cast<DWORD>(MAX_PATH));
+
+  return base::FilePath(buffer);
+}
+
+std::wstring GetValidatedModuleValue(const base::CommandLine& command_line,
+                                     const base::FilePath& exe_path) {
+  // Allow module value configuration if the bootstrap executable has the
+  // default name.
+  const auto& value = GetModuleValue(command_line);
+  if (!value.empty() && IsDefaultExeName(NamePart(exe_path))) {
+    return value;
+  }
+  return std::wstring();
+}
+
+std::wstring GetDefaultModuleValue(const base::FilePath& exe_path) {
+  return NamePart(exe_path);
+}
+
+bool IsModulePathAllowed(HMODULE module, const base::FilePath& exe_path) {
+  // Allow any module path if the bootstrap executable has the default name.
+  if (IsDefaultExeName(NamePart(exe_path))) {
+    return true;
+  }
+
+  const auto& module_path = GetModulePath(module);
+
+  // Module must be at the same path as the executable.
+  return module_path.DirName() == exe_path.DirName();
+}
+
+}  // namespace bootstrap_util