/usr/lib/llvm-3.5/include/clang/Serialization/ is in libclang-3.5-dev 1:3.5-4ubuntu2~trusty2.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/llvm-3.5/include/clang/Serialization/ASTBitCodes.h
/usr/lib/llvm-3.5/include/clang/Serialization/ASTDeserializationListener.h
/usr/lib/llvm-3.5/include/clang/Serialization/ASTReader.h
/usr/lib/llvm-3.5/include/clang/Serialization/ASTWriter.h
/usr/lib/llvm-3.5/include/clang/Serialization/AttrPCHRead.inc
/usr/lib/llvm-3.5/include/clang/Serialization/AttrPCHWrite.inc
/usr/lib/llvm-3.5/include/clang/Serialization/ContinuousRangeMap.h
/usr/lib/llvm-3.5/include/clang/Serialization/GlobalModuleIndex.h
/usr/lib/llvm-3.5/include/clang/Serialization/Module.h
/usr/lib/llvm-3.5/include/clang/Serialization/ModuleManager.h
/usr/lib/llvm-3.5/include/clang/Serialization/SerializationDiagnostic.h