quic_flags_impl: Fix GCC build after #618558

Due to https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84849, having
base::NoDestructor<T<U>> and passing an initializer list of Us does not
work if this is not done explicitly, as GCC incorrectly fails to determine
which constructor overload to use:

    ../../net/third_party/quic/platform/impl/quic_flags_impl.cc: In member function ‘bool quic::TypedQuicFlagHelper<T>::SetFlag(const string&) const [with T = bool; std::__cxx11::string = std::__cxx11::basic_string<char>]’:
    ../../net/third_party/quic/platform/impl/quic_flags_impl.cc:156:41: error: call of overloaded ‘NoDestructor(<brace-enclosed initializer list>)’ is ambiguous
           {"", "1", "t", "true", "y", "yes"});
                                         ^
    In file included from ../../net/third_party/quic/platform/impl/quic_flags_impl.h:16,
                     from ../../net/third_party/quic/platform/impl/quic_flags_impl.cc:5:
    ../../base/no_destructor.h:62:3: note: candidate: ‘base::NoDestructor<T>::NoDestructor(const base::NoDestructor<T>&) [with T = std::set<std::__cxx11::basic_string<char> >]’ <deleted>
       NoDestructor(const NoDestructor&) = delete;
       ^~~~~~~~~~~~
    ../../base/no_destructor.h:60:12: note: candidate: ‘base::NoDestructor<T>::NoDestructor(T&&) [with T = std::set<std::__cxx11::basic_string<char> >]’
       explicit NoDestructor(T&& x) { new (storage_) T(std::move(x)); }
                ^~~~~~~~~~~~
    ../../base/no_destructor.h:59:12: note: candidate: ‘base::NoDestructor<T>::NoDestructor(const T&) [with T = std::set<std::__cxx11::basic_string<char> >]’
       explicit NoDestructor(const T& x) { new (storage_) T(x); }
                ^~~~~~~~~~~~

Explicitly use an std::initializer_list to make the build work everywhere.

Bug: 819294
Change-Id: I775be20e3766a88a656b58c94c40869cb1bee2a8
Reviewed-on: https://chromium-review.googlesource.com/c/1458214
Auto-Submit: Raphael Kubo da Costa <raphael.kubo.da.costa@intel.com>
Reviewed-by: Ryan Hamilton <rch@chromium.org>
Commit-Queue: Raphael Kubo da Costa <raphael.kubo.da.costa@intel.com>
Cr-Commit-Position: refs/heads/master@{#630249}
1 file changed