Reconnect to debugger after reload

Summary:
This diff allows re-connecting to the debugger websocket after reloading so that if, for example, metro has restarted, we'll reconnect to allow for debugging. Previously you would need to kill the app and re-open it to re-register the debugger websocket.

Changelog: [iOS] [Fixed] Reconnect to debugger websocket after metro is restarted.

Reviewed By: motiz88

Differential Revision: D18820399

fbshipit-source-id: ddbfa4476e70a6313c877a050ef2d77c04d1657e

React/DevSupport/RCTInspectorDevServerHelper.mm

@@ -128,7 +128,7 @@ + (RCTInspectorPackagerConnection *)connectWithBundleURL:(NSURL *)bundleURL
 
   NSString *key = [inspectorURL absoluteString];
   RCTInspectorPackagerConnection *connection = socketConnections[key];
-  if (!connection) {
+  if (!connection || !connection.isConnected) {
     connection = [[RCTInspectorPackagerConnection alloc] initWithURL:inspectorURL];
     socketConnections[key] = connection;
     [connection connect];

React/Inspector/RCTInspectorPackagerConnection.h

@@ -20,6 +20,7 @@ typedef RCTBundleStatus *(^RCTBundleStatusProvider)(void);
 @interface RCTInspectorPackagerConnection : NSObject
 - (instancetype)initWithURL:(NSURL *)url;
 
+- (bool)isConnected;
 - (void)connect;
 - (void)closeQuietly;
 - (void)sendEventToAllConnections:(NSString *)event;

React/Inspector/RCTInspectorPackagerConnection.m

@@ -241,6 +241,11 @@ - (void)webSocket:(__unused RCTSRWebSocket *)webSocket didCloseWithCode:(__unuse
   }
 }
 
+- (bool)isConnected
+{
+  return _webSocket != nil;
+}
+
 - (void)connect
 {
   if (_closed) {