Put helper classes in an anonymous namespace.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@185301 91177308-0d34-0410-b5e6-96231b3b80d8
Use LLVM_DELETED_FUNCTION on unimplemented copy constructor and assignment operator.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@185302 91177308-0d34-0410-b5e6-96231b3b80d8
Put helper classes in an anonymous namespace.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@185303 91177308-0d34-0410-b5e6-96231b3b80d8