service/vi/vi_layer: Convert Layer struct into a class

Like the previous changes made to the Display struct, this prepares the
Layer struct for changes to its interface. Given Layer will be given
more invariants in the future, we convert it into a class to better
signify that.

src/core/hle/service/nvflinger/nvflinger.cpp

@@ -91,7 +91,7 @@ std::optional<u32> NVFlinger::FindBufferQueueId(u64 display_id, u64 layer_id) co
         return {};
     }
 
-    return layer->buffer_queue->GetId();
+    return layer->GetBufferQueue().GetId();
 }
 
 Kernel::SharedPtr<Kernel::ReadableEvent> NVFlinger::FindVsyncEvent(u64 display_id) const {
@@ -167,10 +167,10 @@ void NVFlinger::Compose() {
 
         // TODO(Subv): Support more than 1 layer.
         VI::Layer& layer = display.GetLayer(0);
-        auto& buffer_queue = layer.buffer_queue;
+        auto& buffer_queue = layer.GetBufferQueue();
 
         // Search for a queued buffer and acquire it
-        auto buffer = buffer_queue->AcquireBuffer();
+        auto buffer = buffer_queue.AcquireBuffer();
 
         MicroProfileFlip();
 
@@ -195,7 +195,7 @@ void NVFlinger::Compose() {
                      igbp_buffer.width, igbp_buffer.height, igbp_buffer.stride,
                      buffer->get().transform, buffer->get().crop_rect);
 
-        buffer_queue->ReleaseBuffer(buffer->get().slot);
+        buffer_queue.ReleaseBuffer(buffer->get().slot);
     }
 }
 

src/core/hle/service/nvflinger/nvflinger.h

@@ -29,7 +29,7 @@ class Module;
 
 namespace Service::VI {
 class Display;
-struct Layer;
+class Layer;
 } // namespace Service::VI
 
 namespace Service::NVFlinger {