[Android]fix memory leak in Android

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

@@ -666,6 +666,15 @@ public synchronized void removeRootView(int rootViewTag) {
     mRootTags.delete(rootViewTag);
   }
 
+  /**
+   * Return root view num
+   *
+   * @return The num of root view
+   */
+  public synchronized int getRootViewNum() {
+    return mRootTags.size();
+  }
+
   /**
    * Returns true on success, false on failure. If successful, after calling, output buffer will be
    * {x, y, width, height}.

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

@@ -170,6 +170,15 @@ public void removeRootView(int rootViewTag) {
     mOperationsQueue.enqueueRemoveRootView(rootViewTag);
   }
 
+  /**
+   * Return root view num
+   *
+   * @return The num of root view
+   */
+  private int getRootViewNum() {
+    return mOperationsQueue.getNativeViewHierarchyManager().getRootViewNum();
+  }
+
   /** Unregisters a root node with a given tag from the shadow node registry */
   public void removeRootShadowNode(int rootViewTag) {
     synchronized (uiImplementationThreadLock) {
@@ -599,6 +608,12 @@ public void measureLayoutRelativeToParent(
 
   /** Invoked at the end of the transaction to commit any updates to the node hierarchy. */
   public void dispatchViewUpdates(int batchId) {
+    if (getRootViewNum() <= 0) {
+      // If there are no RootViews registered, there will be no View updates to dispatch.
+      // This is a hack to prevent this from being called when Fabric is used everywhere.
+      // This should no longer be necessary in Bridgeless Mode.
+      return;
+    }
     SystraceMessage.beginSection(
             Systrace.TRACE_TAG_REACT_JAVA_BRIDGE, "UIImplementation.dispatchViewUpdates")
         .arg("batchId", batchId)

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

@@ -113,7 +113,6 @@ public interface CustomEventNamesResolver {
   private volatile int mViewManagerConstantsCacheSize;
 
   private int mBatchId = 0;
-  private int mNumRootViews = 0;
 
   public UIManagerModule(
       ReactApplicationContext reactContext,
@@ -403,7 +402,6 @@ public <T extends View> int addRootView(
             -1);
 
     mUIImplementation.registerRootView(rootView, tag, themedRootContext);
-    mNumRootViews++;
     Systrace.endSection(Systrace.TRACE_TAG_REACT_JAVA_BRIDGE);
     return tag;
   }
@@ -427,7 +425,6 @@ public void stopSurface(final int surfaceId) {
   @ReactMethod
   public void removeRootView(int rootViewTag) {
     mUIImplementation.removeRootView(rootViewTag);
-    mNumRootViews--;
   }
 
   public void updateNodeSize(int nodeViewTag, int newWidth, int newHeight) {
@@ -768,12 +765,7 @@ public void onBatchComplete() {
       listener.willDispatchViewUpdates(this);
     }
     try {
-      // If there are no RootViews registered, there will be no View updates to dispatch.
-      // This is a hack to prevent this from being called when Fabric is used everywhere.
-      // This should no longer be necessary in Bridgeless Mode.
-      if (mNumRootViews > 0) {
-        mUIImplementation.dispatchViewUpdates(batchId);
-      }
+      mUIImplementation.dispatchViewUpdates(batchId);
     } finally {
       Systrace.endSection(Systrace.TRACE_TAG_REACT_JAVA_BRIDGE);
     }