[Jetcaster] Use the ViewModel factory DSL (#1156)

Use the ViewModel factory DSL for simplicity.

https://developer.android.com/topic/libraries/architecture/viewmodel/viewmodel-factories

Jetcaster/app/src/main/java/com/example/jetcaster/util/ViewModel.kt

@@ -18,6 +18,8 @@ package com.example.jetcaster.util
 
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.ViewModelProvider
+import androidx.lifecycle.viewmodel.initializer
+import androidx.lifecycle.viewmodel.viewModelFactory
 
 /**
  * Returns a [ViewModelProvider.Factory] which will return the result of [create] when it's
@@ -26,22 +28,10 @@ import androidx.lifecycle.ViewModelProvider
  * If the created [ViewModel] does not match the requested class, an [IllegalArgumentException]
  * exception is thrown.
  */
-fun <VM : ViewModel> viewModelProviderFactoryOf(
-    create: () -> VM
-): ViewModelProvider.Factory = SimpleFactory(create)
-
-/**
- * This needs to be a named class currently to workaround a compiler issue: b/163807311
- */
-private class SimpleFactory<VM : ViewModel>(
-    private val create: () -> VM
-) : ViewModelProvider.Factory {
-    override fun <T : ViewModel> create(modelClass: Class<T>): T {
-        val vm = create()
-        if (modelClass.isInstance(vm)) {
-            @Suppress("UNCHECKED_CAST")
-            return vm as T
-        }
-        throw IllegalArgumentException("Can not create ViewModel for class: $modelClass")
+inline fun <reified VM : ViewModel> viewModelProviderFactoryOf(
+    crossinline create: () -> VM
+): ViewModelProvider.Factory = viewModelFactory {
+    initializer {
+        create()
     }
 }