Provide root reactTag to RootComponent and use it to resolve view controllers

Libraries/ReactIOS/renderApplication.ios.js

@@ -73,6 +73,7 @@ function renderApplication<D, P, S>(
     <AppContainer rootTag={rootTag}>
       <RootComponent
         {...initialProps}
+        rootTag={rootTag}
       />
     </AppContainer>,
     rootTag

React/Modules/RCTUIManager.h

@@ -34,6 +34,11 @@
  */
 - (void)registerRootView:(UIView *)rootView;
 
+/**
+ * Gets the view associated with a reactTag.
+ */
+- (UIView *)viewForReactTag:(NSNumber *)reactTag;
+
 /**
  * Update the frame of a root view. This might be in response to a screen rotation
  * or some other layout event outside of the React-managed view hierarchy.

React/Modules/RCTUIManager.m

@@ -359,6 +359,12 @@ static NSDictionary *RCTViewConfigForModule(Class managerClass)
   });
 }
 
+- (UIView *)viewForReactTag:(NSNumber *)reactTag
+{
+  RCTAssertMainThread();
+  return _viewRegistry[reactTag];
+}
+
 - (void)setFrame:(CGRect)frame forRootView:(UIView *)rootView
 {
   RCTAssertMainThread();

React/Views/UIView+React.m

@@ -13,7 +13,6 @@
 
 #import "RCTAssert.h"
 #import "RCTLog.h"
-#import "RCTWrapperViewController.h"
 
 @implementation UIView (React)
 
@@ -91,8 +90,11 @@
 - (UIViewController *)backingViewController
 {
   id responder = [self nextResponder];
-  if ([responder isKindOfClass:[RCTWrapperViewController class]]) {
-    return responder;
+  while (responder) {
+    if ([responder isKindOfClass:[UIViewController class]]) {
+      return responder;
+    }
+    responder = [responder nextResponder];
   }
   return nil;
 }