ATrace C++ wrapper API

[DanAlbert]

Forked from https://github.com/android-ndk/ndk/issues/476

Possible API:

namespace android::trace  {
    class Trace  final {
    public:
        Trace  (const std::string& sectionName);
        Trace  (std::string_view sectionName);
        ~Trace  (); // Use RAII to close trace section
 
        static bool isEnabled() noexcept;
        static void beginSection(const std::string& sectionName) noexcept;
        static void beginSection(std::string_view sectionName) noexcept;
        static void endSection() noexcept;
    };
}