Fix headers

Author: brianquinlan

pkgs/cupertino_http/darwin/cupertino_http/Sources/cupertino_http/utils.h

@@ -0,0 +1,20 @@
+#import <Foundation/NSLock.h>
+#import <Foundation/NSURL.h>
+#import <Foundation/NSURLSession.h>
+#include <stdint.h>
+
+#if !__has_feature(objc_arc)
+#error "This file must be compiled with ARC enabled"
+#endif
+
+typedef void (^_DidFinish)(void *closure, NSURLSession *session,
+                           NSURLSessionDownloadTask *downloadTask,
+                           NSURL *location);
+typedef void (^_DidFinishWithLock)(NSCondition *lock, NSURLSession *session,
+                                   NSURLSessionDownloadTask *downloadTask,
+                                   NSURL *location);
+/// Create a block useable as a
+/// `URLSession:downloadTask:didFinishDownloadingToURL:` that can be used to
+/// make an async Dart callback behave synchronously.
+__attribute__((visibility("default"))) __attribute__((used))
+_DidFinish adaptFinishWithLock(_DidFinishWithLock block);

pkgs/cupertino_http/darwin/cupertino_http/Sources/cupertino_http/utils.m

@@ -1,21 +1,6 @@
-#import <Foundation/NSLock.h>
-#import <Foundation/NSURL.h>
-#import <Foundation/NSURLSession.h>
-#include <stdint.h>
+#include "utils.h"
 
-#if !__has_feature(objc_arc)
-#error "This file must be compiled with ARC enabled"
-#endif
-
-typedef void (^_DidFinish)(void *closure, NSURLSession *session,
-                           NSURLSessionDownloadTask *downloadTask,
-                           NSURL *location);
-typedef void (^_DidFinishWithLock)(NSCondition *lock, NSURLSession *session,
-                                   NSURLSessionDownloadTask *downloadTask,
-                                   NSURL *location);
-
-__attribute__((visibility("default"))) __attribute__((used)) _DidFinish
-adaptFinishWithLock(_DidFinishWithLock block) {
+_DidFinish adaptFinishWithLock(_DidFinishWithLock block) {
   return ^void(void *closure, NSURLSession *session,
                NSURLSessionDownloadTask *downloadTask, NSURL *location) {
     NSCondition *lock = [[NSCondition alloc] init];