isExpression and getValue integration for new property values

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

@@ -46,7 +46,7 @@ public boolean isNull() {
    * @return true if this is a expression, false if not
    */
   public boolean isExpression() {
-    return !isNull() && value instanceof JsonArray;
+    return !isNull() && (value instanceof JsonArray || value instanceof Expression);
   }
 
   /**
@@ -57,7 +57,9 @@ public boolean isExpression() {
   @Nullable
   public Expression getExpression() {
     if (isExpression()) {
-      return Expression.Converter.convert((JsonArray) value);
+      return value instanceof JsonArray
+        ? Expression.Converter.convert((JsonArray) value)
+        : (Expression) value;
     } else {
       Logger.w(TAG, "not a expression, try value");
       return null;

platform/android/MapboxGLAndroidSDK/src/test/java/com/mapbox/mapboxsdk/style/expressions/ExpressionTest.java

@@ -4,6 +4,7 @@
 
 import com.mapbox.mapboxsdk.style.layers.PropertyFactory;
 
+import com.mapbox.mapboxsdk.style.layers.PropertyValue;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.robolectric.RobolectricTestRunner;
@@ -87,6 +88,7 @@
 import static com.mapbox.mapboxsdk.style.expressions.Expression.var;
 import static com.mapbox.mapboxsdk.style.expressions.Expression.zoom;
 import static com.mapbox.mapboxsdk.style.layers.PropertyFactory.lineOpacity;
+import static com.mapbox.mapboxsdk.style.layers.PropertyFactory.lineWidth;
 import static junit.framework.Assert.assertTrue;
 import static org.junit.Assert.assertEquals;
 
@@ -96,6 +98,18 @@
 @RunWith(RobolectricTestRunner.class)
 public class ExpressionTest {
 
+  @Test
+  public void testPropertyValueIsExpression() {
+    PropertyValue<?> property = lineWidth(Expression.get("width"));
+    assertTrue(property.isExpression());
+  }
+
+  @Test
+  public void testPropertyValueEqualsExpression() {
+    PropertyValue<?> property = lineWidth(Expression.get("width"));
+    assertEquals(Expression.get("width"), property.getExpression());
+  }
+
   @Test
   public void testRgb() throws Exception {
     Object[] expected = new Object[] {"rgb", 0f, 0f, 0f};