Add BufferReleaseChannel

BufferReleaseChannel will be used to communicate buffer releases from SurfaceFlinger to BLASTBufferQueue.

Bug: 294133380
Flag: com.android.graphics.libgui.flags.buffer_release_channel
Test: BufferReleaseChannelTest
Change-Id: Ic38e8eefc96abc0b2bbe780115b7628413e8b829
diff --git a/libs/gui/tests/Android.bp b/libs/gui/tests/Android.bp
index b342a7d..9558eda 100644
--- a/libs/gui/tests/Android.bp
+++ b/libs/gui/tests/Android.bp
@@ -33,6 +33,7 @@
         "BLASTBufferQueue_test.cpp",
         "BufferItemConsumer_test.cpp",
         "BufferQueue_test.cpp",
+        "BufferReleaseChannel_test.cpp",
         "Choreographer_test.cpp",
         "CompositorTiming_test.cpp",
         "CpuConsumer_test.cpp",