Merge branch 'release-boba' into masterupstream/fabian-merge-v4.0.0

# Conflicts:
#	circle.yml
#	include/mbgl/style/expression/let.hpp
#	platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/geometry/LatLngBounds.java
#	platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/maps/MapGestureDetector.java
#	platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/maps/MapKeyListener.java
#	platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/maps/MapView.java
#	platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/maps/MapboxMap.java
#	platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/maps/Projection.java
#	platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/maps/Transform.java
#	platform/android/MapboxGLAndroidSDK/src/test/java/com/mapbox/mapboxsdk/geometry/LatLngBoundsTest.java
#	platform/android/MapboxGLAndroidSDKTestApp/src/main/AndroidManifest.xml
#	platform/android/gradle/dependencies.gradle
#	platform/android/src/example_custom_layer.cpp
#	platform/android/src/geojson/point.cpp
#	platform/darwin/src/NSPredicate+MGLAdditions.mm
#	platform/darwin/test/MGLExpressionTests.mm
#	platform/ios/Mapbox-iOS-SDK-nightly-dynamic.podspec
#	platform/ios/Mapbox-iOS-SDK-symbols.podspec
#	platform/ios/Mapbox-iOS-SDK.podspec
#	platform/ios/app/MBXViewController.m
#	src/mbgl/renderer/layers/render_custom_layer.cpp
#	src/mbgl/style/conversion/filter.cpp
#	src/mbgl/style/expression/interpolate.cpp
#	src/mbgl/style/expression/value.cpp
#	test/style/filter.test.cpp

1 files changed, 28 insertions, 0 deletions

diff --git a/platform/android/src/gson/json_element.cpp b/platform/android/src/gson/json_element.cpp
index 060b1e0fe2..5eaaf531f4 100644
--- a/platform/android/src/gson/json_element.cpp
+++ b/platform/android/src/gson/json_element.cpp
@@ -11,6 +11,34 @@ namespace mbgl {
 namespace android {
 namespace gson {
 
+/**
+ * Turn mapbox::geometry::value into Java Gson JsonElement
+ */
+class JsonElementEvaluator {
+public:
+
+    jni::JNIEnv& env;
+
+    jni::Object<JsonElement> operator()(const JsonPrimitive::value value) const {
+        return jni::Cast(env, JsonPrimitive::New(env, value), JsonElement::javaClass);
+    }
+
+    jni::Object<JsonElement> operator()(const std::vector<mapbox::geometry::value> &values) const {
+        return jni::Cast(env, JsonArray::New(env, values), JsonElement::javaClass);
+    }
+
+    jni::Object<JsonElement> operator()(const std::unordered_map<std::string, mapbox::geometry::value> &values) const {
+        return jni::Cast(env, JsonObject::New(env, values), JsonElement::javaClass);
+    }
+
+};
+
+
+jni::Object<JsonElement> JsonElement::New(jni::JNIEnv& env, const mapbox::geometry::value& value) {
+  JsonElementEvaluator evaluator { env } ;
+  return mapbox::geometry::value::visit(value, evaluator);
+}
+
 mapbox::geometry::value JsonElement::convert(jni::JNIEnv &env, jni::Object<JsonElement> jsonElement) {
     mapbox::geometry::value value;