[android] Expose pre-fetching zoom delta. (#15769)

* [android] Expose pre-fetching zoom delta.

* [android] Fix Clang format.

* [android] Add MapboxMap unit test.

* [android] Add prefetching zoom delta into MapboxMapOptions.

* [android] Deprecate setPrefetchesTiles to migrate to setPrefetchZoomDelta.

* [android] Deprecate getPrefetchesTiles() and migrate to setPrefetchZoomDelta().

* [android] Add unit test to NativeMapViewTest.

* [android] Add IntRange annotation to getPrefetchZoomDelta.

platform/android/MapboxGLAndroidSDK/src/test/java/com/mapbox/mapboxsdk/maps/MapboxMapOptionsTest.java

@@ -167,6 +167,16 @@ public class MapboxMapOptionsTest {
     assertFalse(new MapboxMapOptions().setPrefetchesTiles(false).getPrefetchesTiles());
   }
 
+  @Test
+  public void testPrefetchZoomDelta() {
+    // Default value
+    assertEquals(4, new MapboxMapOptions().getPrefetchZoomDelta());
+
+    // Check mutations
+    assertEquals(5, new MapboxMapOptions().setPrefetchZoomDelta(5).getPrefetchZoomDelta());
+  }
+
+
   @Test
   public void testCrossSourceCollisions() {
     // Default value

platform/android/MapboxGLAndroidSDK/src/test/java/com/mapbox/mapboxsdk/maps/MapboxMapTest.kt

@@ -126,6 +126,18 @@ class MapboxMapTest {
     verify { nativeMapView.prefetchTiles = true }
   }
 
+  @Test
+  fun testGetPrefetchZoomDelta() {
+    every { nativeMapView.prefetchZoomDelta } answers { 3 }
+    assertEquals(3, mapboxMap.prefetchZoomDelta)
+  }
+
+  @Test
+  fun testSetPrefetchZoomDelta() {
+    mapboxMap.prefetchZoomDelta = 2
+    verify { nativeMapView.prefetchZoomDelta = 2 }
+  }
+
   @Test
   fun testCameraForLatLngBounds() {
     val bounds = LatLngBounds.Builder().include(LatLng()).include(LatLng(1.0, 1.0)).build()