Remove unused removeRootView() method from FabricUIManager

Summary:
FabricUIManager.removeRootView() isn't currently used, removing it from the UIManager interface.

It looks like this is called from JS in paper renderers, but not Fabric, so we should be good to delete it.

Reviewed By: shergin, mdvacca

Differential Revision: D16275118

fbshipit-source-id: b8f3ae1dc7574ce17d8cc9e7fee72ef5dcc9b323

ReactAndroid/src/main/java/com/facebook/react/bridge/UIManager.java

@@ -15,9 +15,6 @@ public interface UIManager extends JSIModule, PerformanceCounter {
   <T extends View> int addRootView(
       final T rootView, WritableMap initialProps, @Nullable String initialUITemplate);
 
-  /** Unregisters a new root view. */
-  void removeRootView(int reactRootTag);
-
   /**
    * Updates the layout specs of the RootShadowNode based on the Measure specs received by
    * parameters.

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

@@ -182,16 +182,6 @@ public void onRequestEventBeat() {
     mEventDispatcher.dispatchAllEvents();
   }
 
-  @Override
-  public void removeRootView(int reactRootTag) {
-    // TODO T31905686: integrate with the unmounting of Fabric React Renderer.
-    mMountingManager.removeRootView(reactRootTag);
-    mReactContextForRootTag.remove(reactRootTag);
-    if (DEBUG) {
-      FLog.d(TAG, "Removing surface for reactTag: ", reactRootTag);
-    }
-  }
-
   @Override
   public void initialize() {
     mEventDispatcher.registerEventEmitter(FABRIC, new FabricEventEmitter(this));

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

@@ -421,6 +421,7 @@ public <T extends View> int addRootView(
     return tag;
   }
 
+  /** Unregisters a new root view. */
   @ReactMethod
   public void removeRootView(int rootViewTag) {
     mUIImplementation.removeRootView(rootViewTag);