Ported TabBarIOS to OSS and unified implementation

ReactKit/Views/RCTViewControllerProtocol.h

@@ -0,0 +1,13 @@
+// Copyright 2004-present Facebook. All Rights Reserved.
+
+/**
+ * A simple protocol that any React-managed ViewControllers should implement.
+ * We need all of our ViewControllers to cache layoutGuide changes so any View
+ * in our View hierarchy can access accurate layoutGuide info at any time.
+ */
+@protocol RCTViewControllerProtocol <NSObject>
+
+@property (nonatomic, readonly, strong) id<UILayoutSupport> currentTopLayoutGuide;
+@property (nonatomic, readonly, strong) id<UILayoutSupport> currentBottomLayoutGuide;
+
+@end