reactBridgeDidFinishTransaction was finally removed

Summary:
We are removing `reactBridgeDidFinishTransaction`.
Why?
 * It is a performance drain. Supporting this requires dispatching main-thread block on every single transaction complete;
 * It has "too broad" non-conceptual semantic which encouraged using this as a "band-aid solution" for poorly designed components;
 * It is conceptually incompatible with new approaches that we are trying to implement to optimize the render layer;
 * It was deprecated for very long time.

Reviewed By: mmmulani

Differential Revision: D6549729

fbshipit-source-id: 58094aab982c67cec3d7fa3b616c637cb84d697f

Author: shergin

React/Modules/RCTUIManager.m

@@ -68,8 +68,6 @@ @implementation RCTUIManager
 
   // Keyed by viewName
   NSDictionary *_componentDataByName;
-
-  NSMutableSet<id<RCTComponent>> *_bridgeTransactionListeners;
 }
 
 @synthesize bridge = _bridge;
@@ -107,7 +105,6 @@ - (void)invalidate
     self->_rootViewTags = nil;
     self->_shadowViewRegistry = nil;
     self->_viewRegistry = nil;
-    self->_bridgeTransactionListeners = nil;
     self->_bridge = nil;
 
     [[NSNotificationCenter defaultCenter] removeObserver:self];
@@ -145,7 +142,6 @@ - (void)setBridge:(RCTBridge *)bridge
   _pendingUIBlocks = [NSMutableArray new];
   _rootViewTags = [NSMutableSet new];
 
-  _bridgeTransactionListeners = [NSMutableSet new];
   _observerCoordinator = [RCTUIManagerObserverCoordinator new];
 
   // Get view managers from bridge
@@ -448,10 +444,6 @@ - (void)_purgeChildren:(NSArray<id<RCTComponent>> *)children
         [(id<RCTInvalidating>)subview invalidate];
       }
       [registry removeObjectForKey:subview.reactTag];
-
-      if (registry == (NSMutableDictionary<NSNumber *, id<RCTComponent>> *)self->_viewRegistry) {
-        [self->_bridgeTransactionListeners removeObject:subview];
-      }
     });
   }
 }
@@ -996,9 +988,7 @@ - (void)_manageChildren:(NSNumber *)containerTag
       if ([view respondsToSelector:@selector(setBackgroundColor:)]) {
         ((UIView *)view).backgroundColor = backgroundColor;
       }
-      if ([view respondsToSelector:@selector(reactBridgeDidFinishTransaction)]) {
-        [uiManager->_bridgeTransactionListeners addObject:view];
-      }
+
       uiManager->_viewRegistry[reactTag] = view;
 
 #if RCT_DEV
@@ -1117,15 +1107,6 @@ - (void)_layoutAndMount
     [self _amendPendingUIBlocksWithStylePropagationUpdateForShadowView:rootView];
   }
 
-  [self addUIBlock:^(RCTUIManager *uiManager, __unused NSDictionary<NSNumber *, UIView *> *viewRegistry) {
-    /**
-     * TODO(tadeu): Remove it once and for all
-     */
-    for (id<RCTComponent> node in uiManager->_bridgeTransactionListeners) {
-      [node reactBridgeDidFinishTransaction];
-    }
-  }];
-
   [_observerCoordinator uiManagerWillPerformMounting:self];
 
   [self flushUIBlocksWithCompletion:^{

React/Views/RCTComponent.h

@@ -50,11 +50,6 @@ typedef void (^RCTBubblingEventBlock)(NSDictionary *body);
  */
 - (void)didUpdateReactSubviews;
 
-// TODO: Deprecate this
-// This method is called after layout has been performed for all views known
-// to the RCTViewManager. It is only called on UIViews, not shadow views.
-- (void)reactBridgeDidFinishTransaction;
-
 @end
 
 // TODO: this is kinda dumb - let's come up with a