Add ptr_util.h from base until std::make_unique<> available

core/fxcrt/fx_memory.h

Index: core/fxcrt/fx_memory.h
diff --git a/core/fxcrt/fx_memory.h b/core/fxcrt/fx_memory.h
index beb194fbda4507b1e26f6a8c8fc0498b8671d4d6..0ad28ce896114da99d2ee850cae72e86ba341516 100644
--- a/core/fxcrt/fx_memory.h
+++ b/core/fxcrt/fx_memory.h
@@ -101,12 +101,6 @@ struct ReleaseDeleter {
   inline void operator()(T* ptr) const { ptr->Release(); }
 };
 
-// Used to help transfer ownership of a raw pointer to std::unique_ptr.
-template <typename T>
-std::unique_ptr<T> WrapUnique(T* ptr) {
-  return std::unique_ptr<T>(ptr);
-}
-
 #endif  // __cplusplus
 
 #endif  // CORE_FXCRT_FX_MEMORY_H_