hle: nvflinger: Add android buffer queue definitions to its own header.

src/core/CMakeLists.txt

@@ -538,6 +538,7 @@ add_library(core STATIC
     hle/service/nvflinger/buffer_queue.cpp
     hle/service/nvflinger/buffer_queue.h
     hle/service/nvflinger/binder.h
+    hle/service/nvflinger/buffer_queue_defs.h
     hle/service/nvflinger/buffer_transform_flags.h
     hle/service/nvflinger/consumer_listener.h
     hle/service/nvflinger/nvflinger.cpp

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

@@ -0,0 +1,21 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+// Copyright 2021 yuzu Emulator Project
+// Copyright 2014 The Android Open Source Project
+// Parts of this implementation were base on:
+// https://cs.android.com/android/platform/superproject/+/android-5.1.1_r38:frameworks/native/include/gui/BufferQueueDefs.h
+
+#pragma once
+
+#include <array>
+
+#include "common/common_types.h"
+#include "core/hle/service/nvflinger/buffer_slot.h"
+
+namespace android::BufferQueueDefs {
+
+// BufferQueue will keep track of at most this value of buffers.
+constexpr s32 NUM_BUFFER_SLOTS = 64;
+
+using SlotsType = std::array<BufferSlot, NUM_BUFFER_SLOTS>;
+
+} // namespace android::BufferQueueDefs