Allow update of state to receive null objects

Summary:
This diff changes updateState method to support null stateWrappers, before this method would crash with a NullPointerException, now it allows the null object to reach the view manager.

Changelog: Add support for update of nullable localState in Fabric

Reviewed By: JoshuaGross

Differential Revision: D17939651

fbshipit-source-id: c62555905e39f9e0db75b9e1d1b93f33d0560266

ReactAndroid/src/main/java/com/facebook/react/fabric/FabricUIManager.java

@@ -339,7 +339,7 @@ public class FabricUIManager implements UIManager, LifecycleEventListener {
 
   @DoNotStrip
   @SuppressWarnings("unused")
-  private MountItem updateStateMountItem(int reactTag, Object stateWrapper) {
+  private MountItem updateStateMountItem(int reactTag, @Nullable Object stateWrapper) {
     return new UpdateStateMountItem(reactTag, (StateWrapper) stateWrapper);
   }
 

ReactAndroid/src/main/java/com/facebook/react/fabric/mounting/MountingManager.java

@@ -369,11 +369,12 @@ public class MountingManager {
   }
 
   @UiThread
-  public void updateState(final int reactTag, StateWrapper stateWrapper) {
+  public void updateState(final int reactTag, @Nullable StateWrapper stateWrapper) {
     UiThreadUtil.assertOnUiThread();
     ViewState viewState = getViewState(reactTag);
-    ReadableNativeMap newState = stateWrapper.getState();
-    if (viewState.mCurrentState != null && viewState.mCurrentState.equals(newState)) {
+    @Nullable ReadableNativeMap newState = stateWrapper == null ? null : stateWrapper.getState();
+    if ((viewState.mCurrentState != null && viewState.mCurrentState.equals(newState))
+        || (viewState.mCurrentState == null && stateWrapper == null)) {
       return;
     }
     viewState.mCurrentState = newState;

ReactAndroid/src/main/java/com/facebook/react/fabric/mounting/mountitems/UpdateStateMountItem.java

@@ -6,15 +6,16 @@
  */
 package com.facebook.react.fabric.mounting.mountitems;
 
+import androidx.annotation.Nullable;
 import com.facebook.react.fabric.mounting.MountingManager;
 import com.facebook.react.uimanager.StateWrapper;
 
 public class UpdateStateMountItem implements MountItem {
 
   private final int mReactTag;
-  private final StateWrapper mStateWrapper;
+  @Nullable private final StateWrapper mStateWrapper;
 
-  public UpdateStateMountItem(int reactTag, StateWrapper stateWrapper) {
+  public UpdateStateMountItem(int reactTag, @Nullable StateWrapper stateWrapper) {
     mReactTag = reactTag;
     mStateWrapper = stateWrapper;
   }

ReactAndroid/src/main/java/com/facebook/react/uimanager/ViewManager.java

@@ -282,7 +282,7 @@ public abstract class ViewManager<T extends View, C extends ReactShadowNode>
    * this component type.
    */
   public @Nullable Object updateState(
-      @NonNull T view, ReactStylesDiffMap props, StateWrapper stateWrapper) {
+      @NonNull T view, ReactStylesDiffMap props, @Nullable StateWrapper stateWrapper) {
     return null;
   }
 

ReactAndroid/src/main/java/com/facebook/react/views/modal/ReactModalHostManager.java

@@ -84,7 +84,6 @@ public class ReactModalHostManager extends ViewGroupManager<ReactModalHostView>
     view.setStatusBarTranslucent(statusBarTranslucent);
   }
 
-
   @Override
   @ReactProp(name = "hardwareAccelerated")
   public void setHardwareAccelerated(ReactModalHostView view, boolean hardwareAccelerated) {
@@ -139,7 +138,8 @@ public class ReactModalHostManager extends ViewGroupManager<ReactModalHostView>
 
   @Override
   public Object updateState(
-      ReactModalHostView view, ReactStylesDiffMap props, StateWrapper stateWrapper) {
+      ReactModalHostView view, ReactStylesDiffMap props, @Nullable StateWrapper stateWrapper) {
+    // TODO T55794595: Add support for updating state with null stateWrapper
     Point modalSize = ModalHostHelper.getModalHostSize(view.getContext());
     view.updateState(stateWrapper, modalSize.x, modalSize.y);
     return null;

ReactAndroid/src/main/java/com/facebook/react/views/text/ReactTextViewManager.java

@@ -74,7 +74,8 @@ public class ReactTextViewManager
 
   @Override
   public Object updateState(
-      ReactTextView view, ReactStylesDiffMap props, StateWrapper stateWrapper) {
+      ReactTextView view, ReactStylesDiffMap props, @Nullable StateWrapper stateWrapper) {
+    // TODO T55794595: Add support for updating state with null stateWrapper
     ReadableMap attributedString = stateWrapper.getState().getMap("attributedString");
 
     Spannable spanned =