[android] - allow literal expression property arguments

platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/style/expressions/Expression.java

@@ -3582,6 +3582,12 @@ public class Expression {
       return literal;
     }
 
+    @NonNull
+    @Override
+    public Object[] toArray() {
+      return new Object[] {"literal", literal};
+    }
+
     /**
      * Returns a string representation of the expression literal.
      *

platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/style/layers/Layer.java

@@ -2,7 +2,6 @@ package com.mapbox.mapboxsdk.style.layers;
 
 import android.support.annotation.NonNull;
 
-import com.google.gson.JsonArray;
 import com.google.gson.JsonElement;
 import com.mapbox.mapboxsdk.style.expressions.Expression;
 import com.mapbox.mapboxsdk.utils.ThreadUtils;
@@ -27,7 +26,7 @@ public abstract class Layer {
   /**
    * Validates if layer interaction is happening on the UI thread
    */
-  protected void checkThread(){
+  protected void checkThread() {
     ThreadUtils.checkThread("Layer");
   }