[ReactNative] Create private underlying bridge to prevent retain cycles

React/Base/RCTBridge.h

@@ -80,15 +80,6 @@ RCT_EXTERN NSString *RCTBridgeModuleNameForClass(Class bridgeModuleClass);
 __attribute__((used, section("__DATA,RCTImport"))) \
 static const char *__rct_import_##module##_##method##__ = #module"."#method;
 
-/**
- * This method is used to execute a new application script. It is called
- * internally whenever a JS application bundle is loaded/reloaded, but should
- * probably not be used at any other time.
- */
-- (void)enqueueApplicationScript:(NSString *)script
-                             url:(NSURL *)url
-                      onComplete:(RCTJavaScriptCompleteBlock)onComplete;
-
 /**
  * URL of the script that was loaded into the bridge.
  */
@@ -122,14 +113,4 @@ static const char *__rct_import_##module##_##method##__ = #module"."#method;
  */
 - (void)reload;
 
-/**
- * Add a new observer that will be called on every screen refresh.
- */
-- (void)addFrameUpdateObserver:(id<RCTFrameUpdateObserver>)observer;
-
-/**
- * Stop receiving screen refresh updates for the given observer.
- */
-- (void)removeFrameUpdateObserver:(id<RCTFrameUpdateObserver>)observer;
-
 @end