Added support for synchronous methods in native modules on iOS

Reviewed By: javache

Differential Revision: D4947556

fbshipit-source-id: 0ef73dc5d741201e59fef1fc048809afc65c75b5

React/Base/RCTBridgeMethod.h

@@ -17,6 +17,17 @@ typedef NS_ENUM(NSUInteger, RCTFunctionType) {
   RCTFunctionTypeSync,
 };
 
+static inline const char *RCTFunctionDescriptorFromType(RCTFunctionType type) {
+  switch (type) {
+    case RCTFunctionTypeNormal:
+      return "async";
+    case RCTFunctionTypePromise:
+      return "promise";
+    case RCTFunctionTypeSync:
+      return "sync";
+  }
+};
+
 @protocol RCTBridgeMethod <NSObject>
 
 @property (nonatomic, copy, readonly) NSString *JSMethodName;