Added support of direction style property

Summary: Now layout direction (LTR or LTR) can be specified not only for whole app but also for view subtree via `direction` style property.

Reviewed By: mmmulani

Differential Revision: D4510206

fbshipit-source-id: 4e56c5886b6e42f2343165eb76be897e681c5ba4

React/Views/RCTRootShadowView.m

@@ -7,9 +7,10 @@
  * of patent rights can be found in the PATENTS file in the same directory.
  */
 
-#import "RCTI18nUtil.h"
 #import "RCTRootShadowView.h"
 
+#import "RCTI18nUtil.h"
+
 @implementation RCTRootShadowView
 
 /**
@@ -20,9 +21,7 @@
 {
   self = [super init];
   if (self) {
-    if ([[RCTI18nUtil sharedInstance] isRTL]) {
-      YGNodeStyleSetDirection(self.cssNode, YGDirectionRTL);
-    }
+    self.direction = [[RCTI18nUtil sharedInstance] isRTL] ? YGDirectionRTL : YGDirectionLTR;
   }
   return self;
 }

React/Views/RCTShadowView.h

@@ -146,6 +146,11 @@ typedef void (^RCTApplierBlock)(NSDictionary<NSNumber *, UIView *> *viewRegistry
  */
 @property (nonatomic, assign) NSInteger zIndex;
 
+/**
+ * Interface direction (LTR or RTL)
+ */
+@property (nonatomic, assign) YGDirection direction;
+
 /**
  * Clipping properties
  */

React/Views/RCTShadowView.m

@@ -665,6 +665,7 @@ RCT_STYLE_PROPERTY(AlignItems, alignItems, AlignItems, YGAlign)
 RCT_STYLE_PROPERTY(Position, position, PositionType, YGPositionType)
 RCT_STYLE_PROPERTY(FlexWrap, flexWrap, FlexWrap, YGWrap)
 RCT_STYLE_PROPERTY(Overflow, overflow, Overflow, YGOverflow)
+RCT_STYLE_PROPERTY(Direction, direction, Direction, YGDirection)
 RCT_STYLE_PROPERTY(AspectRatio, aspectRatio, AspectRatio, float)
 
 - (void)setBackgroundColor:(UIColor *)color

React/Views/RCTViewManager.m

@@ -317,5 +317,6 @@ RCT_EXPORT_SHADOW_PROPERTY(overflow, YGOverflow)
 RCT_EXPORT_SHADOW_PROPERTY(onLayout, RCTDirectEventBlock)
 
 RCT_EXPORT_SHADOW_PROPERTY(zIndex, NSInteger)
+RCT_EXPORT_SHADOW_PROPERTY(direction, YGDirection)
 
 @end