Partially remove dependency on folly async

Summary:
This change isolates the usage of folly async from Flipper. Is now self-contained in Flipper Folly schedulers.

Users of Flipper can decide not to use the types defined in that header and implement their own.

NOTE: changes are minimal, we are just replacing direct calls to folly event base with a scheduler which simply relays this on to folly.

Reviewed By: fabiomassimo

Differential Revision: D36052198

fbshipit-source-id: 170d64a324a1f1f100224e2622a59cbac3c8b642

iOS/FlipperKit/FlipperWebSocket.h

@@ -9,11 +9,11 @@
 
 #pragma once
 
+#import <Flipper/FlipperScheduler.h>
 #import <Flipper/FlipperSocket.h>
 #import <Flipper/FlipperSocketProvider.h>
 #import <Flipper/FlipperTransportTypes.h>
 #import <folly/dynamic.h>
-#import <folly/io/async/EventBase.h>
 #import <future>
 #import <memory>
 
@@ -67,14 +67,14 @@ class FlipperWebSocketProvider : public FlipperSocketProvider {
   virtual std::unique_ptr<FlipperSocket> create(
       FlipperConnectionEndpoint endpoint,
       std::unique_ptr<FlipperSocketBasePayload> payload,
-      folly::EventBase* eventBase) override {
+      Scheduler* scheduler) override {
     return std::make_unique<FlipperWebSocket>(
         std::move(endpoint), std::move(payload));
   }
   virtual std::unique_ptr<FlipperSocket> create(
       FlipperConnectionEndpoint endpoint,
       std::unique_ptr<FlipperSocketBasePayload> payload,
-      folly::EventBase* eventBase,
+      Scheduler* scheduler,
       ConnectionContextStore* connectionContextStore) override {
     return std::make_unique<FlipperWebSocket>(
         std::move(endpoint), std::move(payload), connectionContextStore);