Set viewTag for RCTTouchEvent to avoid EventID conflict

Summary:
Using target view's reactTag as viewTag for RCTTouchEvent.

Fix issue facebook#9503
Closes facebook#9952

Differential Revision: D3880152

Pulled By: majak

fbshipit-source-id: 1025aae6a6a1d5074496a9e4a6cf7dfebc713dc7

Author: littlesome

React/Base/RCTTouchEvent.h

@@ -18,6 +18,7 @@
 @interface RCTTouchEvent : NSObject <RCTEvent>
 
 - (instancetype)initWithEventName:(NSString *)eventName
+                         reactTag:(NSNumber *)reactTag
                      reactTouches:(NSArray<NSDictionary *> *)reactTouches
                    changedIndexes:(NSArray<NSNumber *> *)changedIndexes
                     coalescingKey:(uint16_t)coalescingKey NS_DESIGNATED_INITIALIZER;

React/Base/RCTTouchEvent.m

@@ -21,11 +21,13 @@ @implementation RCTTouchEvent
 @synthesize viewTag = _viewTag;
 
 - (instancetype)initWithEventName:(NSString *)eventName
+                         reactTag:(NSNumber *)reactTag
                      reactTouches:(NSArray<NSDictionary *> *)reactTouches
                    changedIndexes:(NSArray<NSNumber *> *)changedIndexes
                     coalescingKey:(uint16_t)coalescingKey
 {
   if (self = [super init]) {
+    _viewTag = reactTag;
     _eventName = eventName;
     _reactTouches = reactTouches;
     _changedIndexes = changedIndexes;

React/Base/RCTTouchHandler.m

@@ -199,6 +199,7 @@ - (void)_updateAndDispatchTouches:(NSSet<UITouch *> *)touches
   }
 
   RCTTouchEvent *event = [[RCTTouchEvent alloc] initWithEventName:eventName
+                                                         reactTag:self.view.reactTag
                                                      reactTouches:reactTouches
                                                    changedIndexes:changedIndexes
                                                     coalescingKey:_coalescingKey];