Add a simple ring buffer and use it for holding TFLite model inputs.

Bug: 167946763
Test: atest libinput_tests
Change-Id: I7e50d38ed0c593aebc5fdc6af4b25868505d48bc
diff --git a/libs/input/tests/Android.bp b/libs/input/tests/Android.bp
index 916a8f2..f07164c 100644
--- a/libs/input/tests/Android.bp
+++ b/libs/input/tests/Android.bp
@@ -19,6 +19,7 @@
         "InputEvent_test.cpp",
         "InputPublisherAndConsumer_test.cpp",
         "MotionPredictor_test.cpp",
+        "RingBuffer_test.cpp",
         "TfLiteMotionPredictor_test.cpp",
         "TouchResampling_test.cpp",
         "TouchVideoFrame_test.cpp",