make additional private headers actually private; import all public headers in AsyncDisplayKit.h

AsyncDisplayKit/Private/ASBatchFetching.h

@@ -0,0 +1,36 @@
+/* Copyright (c) 2014-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+#import <UIKit/UIKit.h>
+
+#import "ASBatchContext.h"
+#import "ASScrollDirection.h"
+#import "ASBaseDefines.h"
+
+ASDISPLAYNODE_EXTERN_C_BEGIN
+
+/**
+ @abstract Determine if batch fetching should begin based on the state of the parameters.
+ @param context The batch fetching context that contains knowledge about in-flight fetches.
+ @param scrollDirection The current scrolling direction of the scroll view.
+ @param bounds The bounds of the scrollview.
+ @param contentSize The content size of the scrollview.
+ @param targetOffset The offset that the scrollview will scroll to.
+ @param leadingScreens How many screens in the remaining distance will trigger batch fetching.
+ @return Whether or not the current state should proceed with batch fetching.
+ @discussion This method is broken into a category for unit testing purposes and should be used with the ASTableView and
+ * ASCollectionView batch fetching API.
+ */
+extern BOOL ASDisplayShouldFetchBatchForContext(ASBatchContext *context,
+                                                ASScrollDirection scrollDirection,
+                                                CGRect bounds,
+                                                CGSize contentSize,
+                                                CGPoint targetOffset,
+                                                CGFloat leadingScreens);
+
+ASDISPLAYNODE_EXTERN_C_END