Support inner component _debugOwner in memo

Author: hanq08

packages/react-reconciler/src/ReactFiberBeginWork.new.js

@@ -429,6 +429,9 @@ function updateMemoComponent(
     child.ref = workInProgress.ref;
     child.return = workInProgress;
     workInProgress.child = child;
+    if (__DEV__) {
+      child._debugOwner = workInProgress;
+    }
     return child;
   }
   if (__DEV__) {

packages/react-reconciler/src/__tests__/ReactMemo-test.js

@@ -497,5 +497,21 @@ describe('memo', () => {
         expect(root).toMatchRenderedOutput('1');
       });
     });
+
+    it('inner component of react memo should have _debugOwner set', async () => {
+      const InComponent = React.forwardRef((props, ref) => (<div ref={ref} />));
+      const Outer = React.memo(InComponent);
+      const App = () => {
+        const ref = React.createRef();
+        return (<Outer ref={ref}>Click me! </Outer>);
+      } 
+      ReactNoop.render(<App />);
+      expect(Scheduler).toFlushWithoutYielding();
+      const innerFiber = ReactNoop.getRoot().current.child.child.child;
+      const innerFiberOwner = innerFiber._debugOwner;
+      expect(innerFiber.type.$$typeof).toBe(Symbol.for('react.forward_ref'));
+      expect(innerFiberOwner).not.toBeNull();
+      expect(innerFiberOwner.type.$$typeof).toBe(Symbol.for('react.memo'));
+    })
   }
 });