[tint][core] Remove dead code

Change-Id: I24fba2021d0ea075e78b7bf11b080ebb23cfec07
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/172025
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: dan sinclair <dsinclair@google.com>
Commit-Queue: Ben Clayton <bclayton@google.com>
diff --git a/src/tint/lang/core/type/manager.h b/src/tint/lang/core/type/manager.h
index f02290b..0a9a201 100644
--- a/src/tint/lang/core/type/manager.h
+++ b/src/tint/lang/core/type/manager.h
@@ -172,7 +172,7 @@
               typename _ = std::enable_if<tint::traits::IsTypeOrDerived<TYPE, Type>>,
               typename... ARGS>
     auto* Find(ARGS&&... args) const {
-        return types_.Find<ToType<TYPE>>(std::forward<ARGS>(args)...);
+        return types_.Find<TYPE>(std::forward<ARGS>(args)...);
     }
 
     /// @returns a void type
@@ -501,16 +501,6 @@
     TypeIterator end() const { return types_.end(); }
 
   private:
-    /// ToType<T> is specialized for various `T` types and each specialization contains a single
-    /// `type` alias to the corresponding type deriving from `core::type::Type`.
-    template <typename T>
-    struct ToTypeImpl {
-        using type = T;
-    };
-
-    template <typename T>
-    using ToType = typename ToTypeImpl<T>::type;
-
     /// Unique types owned by the manager
     UniqueAllocator<Type> types_;
     /// Unique nodes (excluding types) owned by the manager