Fix trackball down and movement bugs.

Bug: 2823788
Change-Id: Icb0c392b58f7e735614460b5eb87439cb73ac4f2
diff --git a/libs/ui/InputReader.cpp b/libs/ui/InputReader.cpp
index 403afe7..30e391f 100644
--- a/libs/ui/InputReader.cpp
+++ b/libs/ui/InputReader.cpp
@@ -270,6 +270,10 @@
             device->trackball.accumulator.fields |=
                     InputDevice::TrackballState::Accumulator::FIELD_BTN_MOUSE;
             device->trackball.accumulator.btnMouse = down;
+
+            // Process the trackball change now since we may not receive a sync immediately.
+            onTrackballStateChanged(rawEvent->when, device);
+            device->trackball.accumulator.clear();
             return;
         }
     }