Remove allowDisablingImmediateExecutionOfScheduleMountItems feature flag

Summary:
No longer needed.

Changelog: [Internal]

Reviewed By: mdvacca

Differential Revision: D20747684

fbshipit-source-id: a8077519b7670d72e23267b1c1423556ec97be3f

ReactAndroid/src/main/java/com/facebook/react/ReactRootView.java

@@ -127,11 +127,9 @@ public class ReactRootView extends FrameLayout implements RootView, ReactRoot {
   @Override
   protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
     // TODO: T60453649 - Add test automation to verify behavior of onMeasure
-    setAllowImmediateUIOperationExecution(false);
 
     if (mUseSurface) {
       super.onMeasure(widthMeasureSpec, heightMeasureSpec);
-      setAllowImmediateUIOperationExecution(true);
       return;
     }
 
@@ -185,7 +183,6 @@ public class ReactRootView extends FrameLayout implements RootView, ReactRoot {
       mLastHeight = height;
 
     } finally {
-      setAllowImmediateUIOperationExecution(true);
       Systrace.endSection(TRACE_TAG_REACT_JAVA_BRIDGE);
     }
   }
@@ -443,43 +440,6 @@ public class ReactRootView extends FrameLayout implements RootView, ReactRoot {
     }
   }
 
-  /**
-   * In Fabric, it is possible for MountItems to be scheduled during onMeasure calls, specifically:
-   *
-   * <p>ReactRootView.onMeasure -> ReactRootView.updateRootLayoutSpecs ->
-   * FabricUIManager.updateRootLayoutSpecs -> Binding.setConstraints -> (C++) commit new tree ->
-   * (C++ Android binding) diff tree, schedule mount items -> FabricUIManager.scheduleMountItem
-   *
-   * <p>If called on the main thread, `scheduleMountItem` will execute MountItems synchronously,
-   * causing all ShadowNode updates to be flushed to the view hierarchy, on the main thread, during
-   * an onMeasure call.
-   *
-   * <p>Use this method to disable immediate execution of mount items.
-   *
-   * <p>This is a noop outside in pre-Fabric React Native.
-   */
-  private void setAllowImmediateUIOperationExecution(boolean flag) {
-    final ReactInstanceManager reactInstanceManager = mReactInstanceManager;
-
-    if (reactInstanceManager == null) {
-      return;
-    }
-
-    final ReactContext reactApplicationContext = reactInstanceManager.getCurrentReactContext();
-
-    if (reactApplicationContext == null) {
-      return;
-    }
-
-    @Nullable
-    UIManager uiManager = UIManagerHelper.getUIManager(reactApplicationContext, getUIManagerType());
-    // Ignore calling setAllowImmediateUIOperationExecution if UIManager is not properly
-    // initialized.
-    if (uiManager != null) {
-      uiManager.setAllowImmediateUIOperationExecution(flag);
-    }
-  }
-
   /**
    * Unmount the react application at this root view, reclaiming any JS memory associated with that
    * application. If {@link #startReactApplication} is called, this method must be called before the

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

@@ -81,16 +81,4 @@ public interface UIManager extends JSIModule, PerformanceCounter {
    * @param eventType
    */
   void sendAccessibilityEvent(int reactTag, int eventType);
-
-  /**
-   * When mounting instructions are scheduled on the UI thread, should they be executed immediately?
-   * For Fabric. Should noop in pre-Fabric.
-   *
-   * <p>This should only be called on the UI thread.
-   *
-   * @param flag
-   */
-  @UiThread
-  @ThreadConfined(UI)
-  void setAllowImmediateUIOperationExecution(boolean flag);
 }

ReactAndroid/src/main/java/com/facebook/react/config/ReactFeatureFlags.java

@@ -71,14 +71,6 @@ public class ReactFeatureFlags {
    */
   public static boolean nullifyCatalystInstanceOnDestroy = false;
 
-  /**
-   * Temporary flag that should be removed soon. See FabricUIManager: if this flag is disabled,
-   * mountItems scheduled on the UI thread will *always* be executed synchronously. If this flag is
-   * enabled, users of FabricUIManager may disable immediate execution of scheduled mount items.
-   * TODO T54997838: remove as followup
-   */
-  public static boolean allowDisablingImmediateExecutionOfScheduleMountItems = false;
-
   /**
    * Temporary flag. See UIImplementation: if this flag is enabled, ViewCommands will be queued and
    * executed before any other types of UI operations.

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

@@ -135,13 +135,6 @@ public class FabricUIManager implements UIManager, LifecycleEventListener {
   @NonNull
   private final DispatchUIFrameCallback mDispatchUIFrameCallback;
 
-  /**
-   * Whether or not to immediately, synchronously execute mountItems when they are scheduled on the
-   * UI thread.
-   */
-  @ThreadConfined(UI)
-  private boolean mImmediatelyExecutedMountItemsOnUI = true;
-
   /**
    * This is used to keep track of whether or not the FabricUIManager has been destroyed. Once the
    * Catalyst instance is being destroyed, we should cease all operation here.
@@ -508,17 +501,6 @@ public class FabricUIManager implements UIManager, LifecycleEventListener {
     }
   }
 
-  /**
-   * When mounting instructions are scheduled on the UI thread, should they be executed immediately?
-   * *
-   */
-  @Override
-  @UiThread
-  @ThreadConfined(UI)
-  public void setAllowImmediateUIOperationExecution(boolean flag) {
-    mImmediatelyExecutedMountItemsOnUI = flag;
-  }
-
   /**
    * This method enqueues UI operations directly to the UI thread. This might change in the future
    * to enforce execution order using {@link ReactChoreographer#CallbackType}.
@@ -557,12 +539,7 @@ public class FabricUIManager implements UIManager, LifecycleEventListener {
 
     if (UiThreadUtil.isOnUiThread()) {
       // We only read these flags on the UI thread.
-      boolean immediateExecutionEnabled =
-          !ReactFeatureFlags.allowDisablingImmediateExecutionOfScheduleMountItems
-              || mImmediatelyExecutedMountItemsOnUI;
-      if (immediateExecutionEnabled) {
-        tryDispatchMountItems();
-      }
+      tryDispatchMountItems();
     }
 
     // Post markers outside of lock and after sync mounting finishes its execution

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

@@ -825,11 +825,6 @@ public class UIManagerModule extends ReactContextBaseJavaModule
     }
   }
 
-  @Override
-  public void setAllowImmediateUIOperationExecution(boolean flag) {
-    // Noop outside of Fabric, call directly on FabricUIManager
-  }
-
   /**
    * Schedule a block to be executed on the UI thread. Useful if you need to execute view logic
    * after all currently queued view updates have completed.