Implement react-native-flipper on iOS (#795)

Summary:
Implement the react-native-flipper native module on iOS. Uses very similar abstractions as on Android.

## Changelog

[react-native-flipper] Support iOS
Pull Request resolved: https://github.com/facebook/flipper/pull/795

Test Plan:
Tested using the RN TicTacToe example app

{F228406333}

Reviewed By: mweststrate

Differential Revision: D19853017

Pulled By: priteshrnandgaonkar

fbshipit-source-id: d93d35ff984b9ba75f812c4c8e3c82e4d550f0c0

react-native/react-native-flipper/ios/FlipperReactNativeJavaScriptPluginManager.h

@@ -0,0 +1,43 @@
+/*
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#import <React/RCTBridgeModule.h>
+
+#import <FlipperKit/FlipperClient.h>
+
+NS_ASSUME_NONNULL_BEGIN
+
+@class FlipperModule;
+
+@interface FlipperReactNativeJavaScriptPluginManager : NSObject
+
++ (instancetype)sharedInstance;
+
+- (void)registerPluginWithModule:(FlipperModule *)module
+                        pluginId:(NSString *)pluginId
+                    inBackground:(BOOL)inBackground
+                  statusCallback:(RCTResponseSenderBlock)statusCallback;
+
+- (void)sendWithPluginId:(NSString *)pluginId method:(NSString *)method data:(NSString *)data;
+
+- (void)reportErrorWithMetadata:(NSString *)reason
+                     stackTrace:(NSString *)stackTrace
+                       pluginId:(NSString *)pluginId;
+
+- (void)reportError:(NSString *)error pluginId:(NSString *)pluginId;
+
+- (void)subscribeWithModule:(FlipperModule *)module
+                   pluginId:(NSString *)pluginId
+                     method:(NSString *)method;
+
+- (void)respondSuccessWithResponderId:(NSString *)responderId data:(NSString *)data;
+
+- (void)respondErrorWithResponderId:(NSString *)responderId data:(NSString *)data;
+
+@end
+
+NS_ASSUME_NONNULL_END