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/FlipperModule.m

@@ -0,0 +1,98 @@
+/*
+ * 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 "FlipperModule.h"
+
+#import "FlipperReactNativeJavaScriptPluginManager.h"
+
+@implementation FlipperModule
+{
+  __weak FlipperReactNativeJavaScriptPluginManager *_manager;
+}
+
+- (instancetype)init
+{
+  return [self initWithManager:[FlipperReactNativeJavaScriptPluginManager sharedInstance]];
+}
+
+- (instancetype)initWithManager:(FlipperReactNativeJavaScriptPluginManager *)manager
+{
+  if (self = [super init]) {
+    _manager = manager;
+  }
+  return self;
+}
+
+RCT_EXPORT_MODULE(Flipper)
+
++ (BOOL)requiresMainQueueSetup
+{
+  return NO;
+}
+
+- (NSArray<NSString *> *)supportedEvents
+{
+  return @[
+    @"react-native-flipper-plugin-connect",
+    @"react-native-flipper-plugin-disconnect",
+    @"react-native-flipper-receive-event",
+  ];
+}
+
+- (void)startObserving
+{
+
+}
+
+- (void)stopObserving
+{
+
+}
+
+RCT_EXPORT_METHOD(registerPlugin:(NSString *)pluginId
+                  inBackground:(BOOL)inBackground
+                  statusCallback:(RCTResponseSenderBlock)statusCallback)
+{
+  [_manager registerPluginWithModule:self
+                            pluginId:pluginId
+                        inBackground:inBackground
+                      statusCallback:statusCallback];
+}
+
+RCT_EXPORT_METHOD(send:(NSString *)pluginId method:(NSString *)method data:(NSString *)data)
+{
+  [_manager sendWithPluginId:pluginId method:method data:data];
+}
+
+RCT_EXPORT_METHOD(reportErrorWithMetadata:(NSString *)pluginId
+                  reason:(NSString *)reason
+                  stackTrace:(NSString *)stackTrace)
+{
+  [_manager reportErrorWithMetadata:reason stackTrace:stackTrace pluginId:pluginId];
+}
+
+RCT_EXPORT_METHOD(reportError:(NSString *)pluginId error:(NSString *)error)
+{
+  [_manager reportError:error pluginId:pluginId];
+}
+
+RCT_EXPORT_METHOD(subscribe:(NSString *)pluginId method:(NSString *)method)
+{
+  [_manager subscribeWithModule:self pluginId:pluginId method:method];
+}
+
+RCT_EXPORT_METHOD(respondSuccess:(NSString *)responderId data:(NSString *)data)
+{
+  [_manager respondSuccessWithResponderId:responderId data:data];
+}
+
+RCT_EXPORT_METHOD(respondError:(NSString *)responderId data:(NSString *)data)
+{
+  [_manager respondErrorWithResponderId:responderId data:data];
+}
+
+@end