Summary:
Fixes issue with template argument deduction with enable_shared_from_this as argument
```
#include<memory>
template<class T>
void makeWeak(const std::shared_ptr<T>& x) {}
struct X : public std::enable_shared_from_this<X>{
};
void test() {
X x
makeWeak(x.shared_from_this()); // compilation failed here - it was unable to deduce template parameter of makeWeak
}
```
Reviewed By: jvillard
Differential Revision: D4414788
fbshipit-source-id: 4d19c53
Andrzej Kotulski