Add MotionPredictor API

This API will provide access to motion predictions.

Bug: 167946763
Test: atest InputTests
Change-Id: Ib8bc0debd9714e76520baae6ab8122762525716d

core/api/current.txt

@@ -50628,6 +50628,13 @@ package android.view {
     field public int toolType;
   }
 
+  public final class MotionPredictor {
+    ctor public MotionPredictor(@NonNull android.content.Context);
+    method public boolean isPredictionAvailable(int, int);
+    method @NonNull public java.util.List<android.view.MotionEvent> predict(long);
+    method public void record(@NonNull android.view.MotionEvent);
+  }
+
   public interface OnReceiveContentListener {
     method @Nullable public android.view.ContentInfo onReceiveContent(@NonNull android.view.View, @NonNull android.view.ContentInfo);
   }

core/java/android/view/MotionPredictor.java

@@ -25,10 +25,15 @@ import java.util.Arrays;
 import java.util.List;
 
 /**
- * Calculates motion predictions.
+ * Calculate motion predictions.
  *
- * Add motions here to get predicted events!
- * @hide
+ * Feed motion events to this class in order to generate the predicted events. The prediction
+ * functionality may not be available on all devices. Check if a specific source is supported on a
+ * given input device using #isPredictionAvailable.
+ *
+ * Send all of the events that were received from the system here in order to generate complete,
+ * accurate predictions. When processing the returned predictions, make sure to consider all of the
+ * {@link MotionEvent#getHistoricalAxisValue historical samples}.
  */
 // Acts as a pass-through to the native MotionPredictor object.
 // Do not store any state in this Java layer, or add any business logic here. All of the

tests/MotionPrediction/Android.bp

@@ -26,6 +26,5 @@ package {
 android_app {
     name: "MotionPrediction",
     srcs: ["**/*.kt"],
-    platform_apis: true,
-    certificate: "platform",
+    sdk_version: "current",
 }