bindings: Use std::enable_if_t<T> instead of std::enable_if<T>::type.

The former was introduced in C++14 and is slightly more concise than the
latter. This has no user-visible changes.

Change-Id: Iaabfb3cd52f7d577ab2d26ec6b162dc25292536b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1940184
Commit-Queue: Raphael Kubo da Costa <raphael.kubo.da.costa@intel.com>
Commit-Queue: Kentaro Hara <haraken@chromium.org>
Auto-Submit: Raphael Kubo da Costa <raphael.kubo.da.costa@intel.com>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Cr-Commit-Position: refs/heads/master@{#719951}

third_party/blink/renderer/bindings/core/v8/native_value_traits.h

@@ -36,7 +36,7 @@ struct NativeValueTraitsBase {
 template <typename T>
 struct NativeValueTraitsBase<
     T,
-    typename std::enable_if<std::is_base_of<IDLBase, T>::value>::type> {
+    std::enable_if_t<std::is_base_of<IDLBase, T>::value>> {
   using ImplType = typename T::ImplType;
   STATIC_ONLY(NativeValueTraitsBase);
 };

third_party/blink/renderer/bindings/core/v8/native_value_traits_impl.h

@@ -662,8 +662,7 @@ struct NativeValueTraits<IDLRecord<K, V>>
 template <typename T>
 struct NativeValueTraits<
     T,
-    typename std::enable_if<
-        std::is_base_of<CallbackFunctionBase, T>::value>::type>
+    std::enable_if_t<std::is_base_of<CallbackFunctionBase, T>::value>>
     : public NativeValueTraitsBase<T> {
   static T* NativeValue(v8::Isolate* isolate,
                         v8::Local<v8::Value> value,