Add skstd::remove_pointer_t and use it.

include/private/SkTLogic.h

Index: include/private/SkTLogic.h
diff --git a/include/private/SkTLogic.h b/include/private/SkTLogic.h
index 8d07ba1d38d5e526a905a93565637df8c04f6aa8..0ca0d0f11bc1e53b562059f0a89f59293811569a 100644
--- a/include/private/SkTLogic.h
+++ b/include/private/SkTLogic.h
@@ -31,6 +31,7 @@ template <bool B, typename T = void> using enable_if_t = typename std::enable_if
 template <typename T> using remove_const_t = typename std::remove_const<T>::type;
 template <typename T> using remove_volatile_t = typename std::remove_volatile<T>::type;
 template <typename T> using remove_cv_t = typename std::remove_cv<T>::type;
+template <typename T> using remove_pointer_t = typename std::remove_pointer<T>::type;
 template <typename T> using remove_reference_t = typename std::remove_reference<T>::type;
 template <typename T> using remove_extent_t = typename std::remove_extent<T>::type;