Support invoking and returning arbitrary types from Java sync hooks

Reviewed By: mhorowitz

Differential Revision: D4409900

fbshipit-source-id: 347e33c442b32f64355d343308c218c15cf5a70f

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

@@ -461,6 +461,7 @@ public abstract class BaseJavaModule implements NativeModule {
   }
 
   private static char returnTypeToChar(Class returnClass) {
+    // Keep this in sync with MethodInvoker
     char tryCommon = commonTypeToChar(returnClass);
     if (tryCommon != '\0') {
       return tryCommon;