Make chrome_elf use thunks instead of function pointers.

chrome_elf/thunk_getter.h

Index: chrome_elf/thunk_getter.h
diff --git a/chrome_elf/thunk_getter.h b/chrome_elf/thunk_getter.h
new file mode 100644
index 0000000000000000000000000000000000000000..69dd0eb0ea9f9ec8ddfeaf565386fb4d190e09a6
--- /dev/null
+++ b/chrome_elf/thunk_getter.h
@@ -0,0 +1,14 @@
+// Copyright 2014 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_ELF_THUNK_GETTER_H_
+#define CHROME_ELF_THUNK_GETTER_H_
+
+namespace sandbox {
+class ServiceResolverThunk;
+}
+
+sandbox::ServiceResolverThunk* GetThunk(bool relaxed);
+
+#endif  // CHROME_ELF_THUNK_GETTER_H_