[general] moving ios and android project under ./platform folder

platform/android/MapboxGLAndroidSDK/src/cpp/mapbox.cpp

@@ -0,0 +1,23 @@
+#include "mapbox.hpp"
+
+namespace mbgl {
+namespace android {
+
+jni::Local<jni::Object<AssetManager>> Mapbox::getAssetManager(jni::JNIEnv& env) {
+    static auto& javaClass = jni::Class<Mapbox>::Singleton(env);
+    auto method = javaClass.GetStaticMethod<jni::Object<AssetManager>()>(env, "getAssetManager");
+    return javaClass.Call(env, method);
+}
+
+jboolean Mapbox::hasInstance(jni::JNIEnv& env) {
+    static auto& javaClass = jni::Class<Mapbox>::Singleton(env);
+    auto method = javaClass.GetStaticMethod<jboolean()>(env, "hasInstance");
+    return javaClass.Call(env, method);
+}
+
+void Mapbox::registerNative(jni::JNIEnv& env) {
+    jni::Class<Mapbox>::Singleton(env);
+}
+
+} // namespace android
+} // namespace mbgl