Remove skstd::is_convertible.

include/private/SkTLogic.h

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  *
  *
  * This header provides some of the helpers (like std::enable_if_t) which will
  * become available with C++14 in the type_traits header (in the skstd
  * namespace). This header also provides several Skia specific additions such
@@ skipping 65 matching lines @@
                              __GLIBCXX__ == SK_GLIBCXX_4_5_4 || \
                              __GLIBCXX__ == SK_GLIBCXX_4_6_4)
 template <typename T> struct underlying_type {
     using type = __underlying_type(T);
 };
 #else
 template <typename T> using underlying_type = std::underlying_type<T>;
 #endif
 template <typename T> using underlying_type_t = typename skstd::underlying_type<T>::type;
 
-template <typename S, typename D,
-          bool=std::is_void<S>::value || is_function<D>::value || std::is_array<D>::value>
-struct is_convertible_detector {
-    static const/*expr*/ bool value = std::is_void<D>::value;
-};
-template <typename S, typename D> struct is_convertible_detector<S, D, false> {
-    using yes_type = uint8_t;
-    using no_type = uint16_t;
-
-    template <typename To> static void param_convertable_to(To);
-
-    template <typename From, typename To>
-    static decltype(param_convertable_to<To>(std::declval<From>()), yes_type()) convertible(int);
-
-    template <typename, typename> static no_type convertible(...);
-
-    static const/*expr*/ bool value = sizeof(convertible<S, D>(0)) == sizeof(yes_type);
-};
-// std::is_convertable is known to be broken (not work with incomplete types) in Android clang NDK.
-// This is currently what prevents us from using std::unique_ptr.
-template<typename S, typename D> struct is_convertible
-    : bool_constant<is_convertible_detector<S, D>::value> {};
-
 }  // namespace skstd
 
 // The sknonstd namespace contains things we would like to be proposed and feel std-ish.
 namespace sknonstd {
 
 // The name 'copy' here is fraught with peril. In this case it means 'append', not 'overwrite'.
 // Alternate proposed names are 'propagate', 'augment', or 'append' (and 'add', but already taken).
 // std::experimental::propagate_const already exists for other purposes in TSv2.
 // These also follow the <dest, source> pattern used by boost.
 template <typename D, typename S> struct copy_const {
@@ skipping 20 matching lines @@
 template <typename D, typename S> using same_volatile_t = typename same_volatile<D, S>::type;
 template <typename D, typename S> using same_cv = copy_cv<skstd::remove_cv_t<D>, S>;
 template <typename D, typename S> using same_cv_t = typename same_cv<D, S>::type;
 
 }  // namespace sknonstd
 
 // Just a pithier wrapper for enable_if_t.
 #define SK_WHEN(condition, T) skstd::enable_if_t<!!(condition), T>
 
 #endif