[XAM] Improvement rollup. Content, enumerators...

- [Kernel] Create guest object for XEnumerator.
- [XAM] Split content data into host/guest variants.
- [XAM] Correct message return type from RESULT to HRESULT.
- [XAM] Add a new dummy content device for ODD.
- [XAM] Implement XamContentAggregateCreateEnumerator.
- [XAM] Implement XamGetPrivateEnumStructureFromHandle.
- [XAM] Implement XMsgCompleteIORequest (sketchy).
- [XAM] Implement XamGetOverlappedResult (sketchy).
- [XAM] Implement XamTaskSchedule (sketchy).

src/xenia/kernel/xenumerator.cc

@@ -20,7 +20,34 @@ XEnumerator::XEnumerator(KernelState* kernel_state, size_t items_per_enumerate,
 
 XEnumerator::~XEnumerator() = default;
 
-void XEnumerator::Initialize() {}
+X_STATUS XEnumerator::Initialize(uint32_t user_index, uint32_t app_id,
+                                 uint32_t message, uint32_t message2,
+                                 uint32_t flags, uint32_t extra_size,
+                                 void** extra_buffer) {
+  auto native_object = CreateNative(sizeof(X_KENUMERATOR) + extra_size);
+  if (!native_object) {
+    return X_STATUS_NO_MEMORY;
+  }
+  auto guest_object = reinterpret_cast<X_KENUMERATOR*>(native_object);
+  guest_object->app_id = app_id;
+  guest_object->message = message;
+  guest_object->message2 = message2;
+  guest_object->user_index = user_index;
+  guest_object->items_per_enumerate =
+      static_cast<uint32_t>(items_per_enumerate_);
+  guest_object->flags = flags;
+  if (extra_buffer) {
+    *extra_buffer =
+        !extra_buffer ? nullptr : &native_object[sizeof(X_KENUMERATOR)];
+  }
+  return X_STATUS_SUCCESS;
+}
+
+X_STATUS XEnumerator::Initialize(uint32_t user_index, uint32_t app_id,
+                                 uint32_t message, uint32_t message2,
+                                 uint32_t flags) {
+  return Initialize(user_index, app_id, message, message2, flags, 0, nullptr);
+}
 
 }  // namespace kernel
 }  // namespace xe