Drop [DynamicallyAccessedMembers] from Marshaler<T>.AbiType (#1461)

* Drop [DAM] from Marshaler<T>.AbiType

* Update ApiCompatBaseline.txt

src/WinRT.Runtime/ApiCompatBaseline.txt

@@ -10,4 +10,5 @@ MembersMustExist : Member 'public System.Delegate System.Delegate ABI.System.Col
 MembersMustExist : Member 'public System.Delegate System.Delegate ABI.System.Collections.Generic.KeyValuePair<K, V>.Vftbl.get_Value_1' does not exist in the implementation but it does exist in the contract.
 TypesMustExist : Type 'ABI.System.Collections.Specialized.INotifyCollectionChanged' does not exist in the implementation but it does exist in the contract.
 TypesMustExist : Type 'ABI.System.ComponentModel.INotifyDataErrorInfo' does not exist in the implementation but it does exist in the contract.
-Total Issues: 11
+CannotRemoveAttribute : Attribute 'System.Diagnostics.CodeAnalysis.DynamicallyAccessedMembersAttribute' exists on 'System.Type WinRT.Marshaler<T>.AbiType' in the contract but not the implementation.
+Total Issues: 12

src/WinRT.Runtime/Marshalers.cs

@@ -1811,14 +1811,16 @@ static Marshaler()
  }
  else
  {
- AbiType = typeof(T).FindHelperType();
- if (AbiType != null)
+ Type abiType = typeof(T).FindHelperType();
+
+ // Could still be blittable and the 'ABI.*' type exists for other reasons (e.g. it's a mapped type)
+ if (abiType?.GetMethod("FromAbi", BindingFlags.Public | BindingFlags.Static) is null)
  {
- // Could still be blittable and the 'ABI.*' type exists for other reasons (e.g. it's a mapped type)
-  if (AbiType.GetMethod("FromAbi", BindingFlags.Public | BindingFlags.Static) == null)
-  {
-  AbiType = null;
- }
+ AbiType = null;
+ }
+ else
+ {
+ AbiType = abiType;
  }
  }
 
@@ -1964,9 +1966,6 @@ static Marshaler()
  RefAbiType = AbiType.MakeByRefType();
  }
 
-#if NET
- [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicMethods)]
-#endif
  public static readonly Type AbiType;
  public static readonly Type RefAbiType;
  public static readonly Func<T, object> CreateMarshaler;