Customize log level in Fantom output

packages/react-native-fantom/runner/runner.js

@@ -187,6 +187,8 @@ module.exports = async function runTest(
       : testBytecodeBundlePath,
     '--featureFlags',
     JSON.stringify(testConfig.flags.common),
+    '--minLogLevel',
+    PRINT_FANTOM_OUTPUT ? 'info' : 'error',
   ]);
 
   if (rnTesterCommandResult.status !== 0) {

packages/react-native/ReactCommon/react/renderer/scheduler/SurfaceHandler.cpp

@@ -22,6 +22,10 @@ SurfaceHandler::SurfaceHandler(
   parameters_.surfaceId = surfaceId;
 }
 
+SurfaceHandler::SurfaceHandler(SurfaceId surfaceId) noexcept {
+  parameters_.surfaceId = surfaceId;
+}
+
 SurfaceHandler::SurfaceHandler(SurfaceHandler&& other) noexcept {
   operator=(std::move(other));
 }
@@ -81,11 +85,15 @@ void SurfaceHandler::start() const noexcept {
 
   link_.shadowTree = shadowTree.get();
 
-  link_.uiManager->startSurface(
-      std::move(shadowTree),
-      parameters.moduleName,
-      parameters.props,
-      parameters_.displayMode);
+  if (!parameters.moduleName.empty()) {
+    link_.uiManager->startSurface(
+        std::move(shadowTree),
+        parameters.moduleName,
+        parameters.props,
+        parameters_.displayMode);
+  } else {
+    link_.uiManager->startEmptySurface(std::move(shadowTree));
+  }
 
   link_.status = Status::Running;
 

packages/react-native/ReactCommon/react/renderer/scheduler/SurfaceHandler.h

@@ -62,6 +62,14 @@ class SurfaceHandler {
    * Can be constructed anytime with a `moduleName` and a `surfaceId`.
    */
   SurfaceHandler(const std::string& moduleName, SurfaceId surfaceId) noexcept;
+
+  /*
+   * Can be constructed anytime with a `surfaceId`.
+   * As the module name is not passed, the surface will have to be rendered
+   * manually by the caller (AppRegistry will not be called).
+   */
+  SurfaceHandler(SurfaceId surfaceId) noexcept;
+
   virtual ~SurfaceHandler() noexcept;
 
   /*

packages/react-native/ReactCommon/react/renderer/scheduler/SurfaceManager.cpp

@@ -37,6 +37,13 @@ void SurfaceManager::startSurface(
   });
 }
 
+void SurfaceManager::startEmptySurface(
+    SurfaceId surfaceId,
+    const LayoutConstraints& layoutConstraints,
+    const LayoutContext& layoutContext) const noexcept {
+  startSurface(surfaceId, "", {}, layoutConstraints, layoutContext);
+}
+
 void SurfaceManager::stopSurface(SurfaceId surfaceId) const noexcept {
   visit(surfaceId, [&](const SurfaceHandler& surfaceHandler) {
     surfaceHandler.stop();

packages/react-native/ReactCommon/react/renderer/scheduler/SurfaceManager.h

@@ -37,6 +37,11 @@ class SurfaceManager final {
       const LayoutConstraints& layoutConstraints = {},
       const LayoutContext& layoutContext = {}) const noexcept;
 
+  void startEmptySurface(
+      SurfaceId surfaceId,
+      const LayoutConstraints& layoutConstraints = {},
+      const LayoutContext& layoutContext = {}) const noexcept;
+
   void stopSurface(SurfaceId surfaceId) const noexcept;
 
   Size measureSurface(

packages/react-native/ReactCommon/react/renderer/uimanager/UIManager.cpp

@@ -242,6 +242,11 @@ void UIManager::startSurface(
   });
 }
 
+void UIManager::startEmptySurface(ShadowTree::Unique&& shadowTree) const {
+  SystraceSection s("UIManager::startEmptySurface");
+  shadowTreeRegistry_.add(std::move(shadowTree));
+}
+
 void UIManager::setSurfaceProps(
     SurfaceId surfaceId,
     const std::string& moduleName,

packages/react-native/ReactCommon/react/renderer/uimanager/UIManager.h

@@ -108,6 +108,8 @@ class UIManager final : public ShadowTreeDelegate {
       const folly::dynamic& props,
       DisplayMode displayMode) const;
 
+  void startEmptySurface(ShadowTree::Unique&& shadowTree) const;
+
   void setSurfaceProps(
       SurfaceId surfaceId,
       const std::string& moduleName,