Use string class names for native modules

Summary: Using strings as keys for module names instead of actuall `.class` prevents additional class loading

Reviewed By: achen1

Differential Revision: D8955006

fbshipit-source-id: 12e6ad35fc35c969c05ca081976cc05b054f6821

ReactAndroid/src/main/java/com/facebook/react/bridge/ModuleSpec.java

@@ -70,6 +70,11 @@ public class ModuleSpec {
     return new ModuleSpec(provider, type.getName());
   }
 
+  public static ModuleSpec nativeModuleSpec(
+      String className, Provider<? extends NativeModule> provider) {
+    return new ModuleSpec(provider, className);
+  }
+
   private ModuleSpec(
       @Nullable Class<? extends NativeModule> type, Provider<? extends NativeModule> provider) {
     mType = type;