[android] - add NonNull to MapboxMap parameter for onMapReady callback, removes necessity to add question mark to all mapboxMap invocations

platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/maps/MapFragment.java

@@ -123,7 +123,7 @@ public final class MapFragment extends Fragment implements OnMapReadyCallback {
    * @param mapboxMap The public api controller of the map
    */
   @Override
-  public void onMapReady(MapboxMap mapboxMap) {
+  public void onMapReady(@NonNull MapboxMap mapboxMap) {
     this.mapboxMap = mapboxMap;
     for (OnMapReadyCallback onMapReadyCallback : mapReadyCallbackList) {
       onMapReadyCallback.onMapReady(mapboxMap);

platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/maps/OnMapReadyCallback.java

@@ -1,5 +1,7 @@
 package com.mapbox.mapboxsdk.maps;
 
+import android.support.annotation.NonNull;
+
 /**
  * Interface definition for a callback to be invoked when the map is ready to be used.
  * <p>
@@ -16,5 +18,5 @@ public interface OnMapReadyCallback {
    * @param mapboxMap An instance of MapboxMap associated with the {@link MapFragment} or
    *                  {@link MapView} that defines the callback.
    */
-  void onMapReady(MapboxMap mapboxMap);
+  void onMapReady(@NonNull MapboxMap mapboxMap);
 }

platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/maps/SupportMapFragment.java

@@ -118,7 +118,7 @@ public class SupportMapFragment extends Fragment implements OnMapReadyCallback {
   }
 
   @Override
-  public void onMapReady(MapboxMap mapboxMap) {
+  public void onMapReady(@NonNull MapboxMap mapboxMap) {
     this.mapboxMap = mapboxMap;
     for (OnMapReadyCallback onMapReadyCallback : mapReadyCallbackList) {
       onMapReadyCallback.onMapReady(mapboxMap);