[Mono.Android] JNIEnv.FindClass(Type) now uses TypeManager

Context: #9811

The .NET MAUI template + NativeAOT currently crashes with:

    02-18 15:59:24.575 12907 12907 E AndroidRuntime: net.dot.jni.internal.JavaProxyThrowable: System.InvalidProgramException: InvalidProgram_Specific, IntPtr Android.Runtime.JNIEnv.monodroid_typemap_managed_to_java(System.Type, Byte*)
    02-18 15:59:24.575 12907 12907 E AndroidRuntime:    at Internal.Runtime.TypeLoaderExceptionHelper.CreateInvalidProgramException(ExceptionStringID, String) + 0x4c
    02-18 15:59:24.575 12907 12907 E AndroidRuntime:    at Android.Runtime.JNIEnv.monodroid_typemap_managed_to_java(Type, Byte*) + 0x18
    02-18 15:59:24.575 12907 12907 E AndroidRuntime:    at Android.Runtime.JNIEnv.TypemapManagedToJava(Type) + 0x104
    02-18 15:59:24.575 12907 12907 E AndroidRuntime:    at Android.Runtime.JNIEnv.GetJniName(Type) + 0x1c
    02-18 15:59:24.575 12907 12907 E AndroidRuntime:    at Android.Runtime.JNIEnv.FindClass(Type) + 0x38
    02-18 15:59:24.575 12907 12907 E AndroidRuntime:    at Android.Runtime.JNIEnv.NewArray(IJavaObject[]) + 0x28
    02-18 15:59:24.575 12907 12907 E AndroidRuntime:    at Android.Runtime.JNIEnv.NewArray[T](T[]) + 0x94
    02-18 15:59:24.575 12907 12907 E AndroidRuntime:    at Android.Graphics.Drawables.LayerDrawable..ctor(Drawable[] layers) + 0xd4
    02-18 15:59:24.575 12907 12907 E AndroidRuntime:    at Microsoft.Maui.Platform.MauiRippleDrawableExtensions.UpdateMauiRippleDrawableBackground(View, Paint, IButtonStroke, Func`1, Func`1, Action) + 0x2ac

This appears to be related to array usage, such as `LayerDrawable.ctor(Drawable[])` in this example.

I can reproduce the same crash using a `ColorStateList.ctor(int[][], int[])` in our NativeAOT "hello world" sample:

    02-19 10:45:29.728 28692 28692 E AndroidRuntime: net.dot.jni.internal.JavaProxyThrowable: System.InvalidProgramException: InvalidProgram_Specific, IntPtr Android.Runtime.JNIEnv.monodroid_typemap_managed_to_java(System.Type, Byte*)
    02-19 10:45:29.728 28692 28692 E AndroidRuntime:    at Internal.Runtime.TypeLoaderExceptionHelper.CreateInvalidProgramException(ExceptionStringID, String) + 0x4c
    02-19 10:45:29.728 28692 28692 E AndroidRuntime:    at Android.Runtime.JNIEnv.monodroid_typemap_managed_to_java(Type, Byte*) + 0x18
    02-19 10:45:29.728 28692 28692 E AndroidRuntime:    at Android.Runtime.JNIEnv.TypemapManagedToJava(Type) + 0x104
    02-19 10:45:29.728 28692 28692 E AndroidRuntime:    at Android.Runtime.JNIEnv.GetJniName(Type) + 0x1c
    02-19 10:45:29.728 28692 28692 E AndroidRuntime:    at Android.Runtime.JNIEnv.FindClass(Type) + 0x38
    02-19 10:45:29.728 28692 28692 E AndroidRuntime:    at Android.Runtime.JNIEnv.NewArray[T](T[]) + 0xa8
    02-19 10:45:29.728 28692 28692 E AndroidRuntime:    at Android.Content.Res.ColorStateList..ctor(Int32[][], Int32[]) + 0xdc
    02-19 10:45:29.728 28692 28692 E AndroidRuntime:    at NativeAOT.MainActivity.OnCreate(Bundle savedInstanceState) + 0xb8

As an alternative to #9811, we can update `JNIEnv.FindClass(Type)` to
go through `TypeManager` instead of using `TypemapManagedToJava`.

After this change, the sample works and prints a log message
indicating `ColorStateList` is created successfully:

    02-19 13:12:25.924  2665  2665 D NativeAOT: MainActivity.OnCreate() ColorStateList: ColorStateList{mThemeAttrs=nullmChangingConfigurations=0mStateSpecs=[[0, 1]]mColors=[0, 1]mDefaultColor=0}

Author: jonathanpeppers

samples/NativeAOT/MainActivity.cs

@@ -1,3 +1,4 @@
+using Android.Content.Res;
 using Android.Runtime;
 using Android.Util;
 using System.Reflection;
@@ -17,5 +18,9 @@ protected override void OnCreate(Bundle? savedInstanceState)
 
         // Set our view from the "main" layout resource
         SetContentView(Resource.Layout.activity_main);
+
+        // An example of an Android API that uses a Java array
+        var list = new ColorStateList (new int[][] { [ 0, 1 ]}, [0, 1]);
+        Log.Debug ("NativeAOT", "MainActivity.OnCreate() ColorStateList: " + list);
     }
 }

src/Mono.Android/Android.Runtime/JNIEnv.cs

@@ -254,12 +254,20 @@ public static unsafe IntPtr CreateInstance (Type type, string signature, params
 
 		public static IntPtr FindClass (System.Type type)
 		{
-			int rank = JavaNativeTypeManager.GetArrayInfo (type, out type);
 			try {
-				return FindClass (JavaNativeTypeManager.ToJniName (GetJniName (type), rank));
+				var sig  = JNIEnvInit.androidRuntime?.TypeManager.GetTypeSignature (type) ?? default;
+				if (!sig.IsValid || sig.SimpleReference == null) {
+					throw new ArgumentException ($"Could not determine Java type corresponding to `{type.AssemblyQualifiedName}`.", nameof (type));
+				}
+
+				JniObjectReference local_ref = JniEnvironment.Types.FindClass (sig.Name);
+				IntPtr global_ref = NewGlobalRef (local_ref.Handle);
+				JniObjectReference.Dispose (ref local_ref);
+				return global_ref;
 			} catch (Java.Lang.Throwable e) {
 				if (!((e is Java.Lang.NoClassDefFoundError) || (e is Java.Lang.ClassNotFoundException)))
 					throw;
+				int rank = JavaNativeTypeManager.GetArrayInfo (type, out type);
 				RuntimeNativeMethods.monodroid_log (LogLevel.Warn, LogCategories.Default, $"JNIEnv.FindClass(Type) caught unexpected exception: {e}");
 				var jni = Java.Interop.TypeManager.GetJniTypeName (type);
 				if (jni != null) {