Fix chrome_elf_unittests to handle dlls being blacklisted before the tests start

chrome_elf/blacklist/blacklist.h

 // Copyright 2013 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_BLACKLIST_BLACKLIST_H_
 #define CHROME_ELF_BLACKLIST_BLACKLIST_H_
 
 #if defined(_WIN64)
 #include "sandbox/win/src/sandbox_nt_types.h"
 #endif
@@ skipping 17 matching lines @@
 // repeatedly fails to start during blacklist setup, it will skip blacklisting
 // on the subsequent run.
 bool LeaveSetupBeacon();
 
 // Looks for the setup running beacon that LeaveSetupBeacon() creates and resets
 // it to to show the setup was successful.
 // Returns true if the beacon was successfully set to BLACKLIST_ENABLED.
 bool ResetBeacon();
 
 // Return the size of the current blacklist.
-int BlacklistSize();
+extern "C" int BlacklistSize();
 
 // Returns if true if the blacklist has been initialized.
 extern "C" bool IsBlacklistInitialized();
 
 // Returns the index of the DLL named |dll_name| on the blacklist, or -1 if not
 // found.
 extern "C" int GetBlacklistIndex(const wchar_t* dll_name);
 
 // Adds the given dll name to the blacklist. Returns true if the dll name is in
 // the blacklist when this returns, false on error. Note that this will copy
@@ skipping 13 matching lines @@
 // The caller doesn't own the strings and isn't expected to free them. These
 // strings won't be hanging unless RemoveDllFromBlacklist is called, but it
 // is only exposed in tests (and should stay that way).
 extern "C" void SuccessfullyBlocked(const wchar_t** blocked_dlls, int* size);
 
 // Add the dlls, originally passed in through finch, from the registry to the
 // blacklist so that they will be blocked identically to those hard coded in.
 extern "C" void AddDllsFromRegistryToBlacklist();
 
 // Record that the dll at the given index was blocked.
-void BlockedDll(size_t blocked_index);
+extern "C" void BlockedDll(size_t blocked_index);
 
 // Initializes the DLL blacklist in the current process. This should be called
 // before any undesirable DLLs might be loaded. If |force| is set to true, then
 // initialization will take place even if a beacon is present. This is useful
 // for tests.
 bool Initialize(bool force);
 
 }  // namespace blacklist
 
 #endif  // CHROME_ELF_BLACKLIST_BLACKLIST_H_