Implement VMRuntime.

(Some of this forwards to unimplemented stuff in Heap.)

Change-Id: I01e51d5673e61ddfdbfa2098310122502c3afcf1
diff --git a/src/jni_internal.cc b/src/jni_internal.cc
index fce79fb..56be2f4 100644
--- a/src/jni_internal.cc
+++ b/src/jni_internal.cc
@@ -107,6 +107,7 @@
   return reinterpret_cast<T>(env->self->DecodeJObject(obj));
 }
 // Explicit instantiations.
+template Array* Decode<Array*>(JNIEnv*, jobject);
 template Class* Decode<Class*>(JNIEnv*, jobject);
 template ClassLoader* Decode<ClassLoader*>(JNIEnv*, jobject);
 template Object* Decode<Object*>(JNIEnv*, jobject);