Use startSurface on Android

Summary:
We currently have two different codepaths for actually rendering a surface with Fabric on iOS and Android: on iOS we use Fabric's `UIManagerBinding.startSurface` to call `AppRegistry.runApplication`, but on Android we don't; instead we use the same codepath as paper, calling `ReactRootView.runApplication`.

This diff does a few different things:
1. Unify iOS and Android by removing the `#ifndef` for Android so that we call `startSurface` for both
2. Pass through the JS module name on Android so that this actually works (it currently passes in an empty string)
3. Remove the call to `ReactRootView.runApplication` for Fabric so that we don't end up doing this twice
4. Copy over some logic that we need from `ReactRootView.runApplication` (make sure that root layout specs get updated, and that content appeared gets logged)

Reviewed By: mdvacca

Differential Revision: D15501666

fbshipit-source-id: 5c96c8cf036261cb99729b1dbdff0f7c09a32d76

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

@@ -1050,16 +1050,24 @@ public class ReactInstanceManager {
   private void attachRootViewToInstance(final ReactRoot reactRoot) {
     Log.d(ReactConstants.TAG, "ReactInstanceManager.attachRootViewToInstance()");
     Systrace.beginSection(TRACE_TAG_REACT_JAVA_BRIDGE, "attachRootViewToInstance");
-    UIManager uiManagerModule = UIManagerHelper.getUIManager(mCurrentReactContext, reactRoot.getUIManagerType());
+    UIManager uiManager = UIManagerHelper.getUIManager(mCurrentReactContext, reactRoot.getUIManagerType());
 
     @Nullable Bundle initialProperties = reactRoot.getAppProperties();
-    final int rootTag = uiManagerModule.addRootView(
-      reactRoot.getRootViewGroup(),
-      initialProperties == null ?
+
+    final int rootTag = uiManager.addRootView(
+        reactRoot.getRootViewGroup(),
+        initialProperties == null ?
             new WritableNativeMap() : Arguments.fromBundle(initialProperties),
         reactRoot.getInitialUITemplate());
     reactRoot.setRootViewTag(rootTag);
-    reactRoot.runApplication();
+    if (reactRoot.getUIManagerType() == FABRIC) {
+      // Fabric requires to call updateRootLayoutSpecs before starting JS Application,
+      // this ensures the root will hace the correct pointScaleFactor.
+      uiManager.updateRootLayoutSpecs(rootTag, reactRoot.getWidthMeasureSpec(), reactRoot.getHeightMeasureSpec());
+      reactRoot.setShouldLogContentAppeared(true);
+    } else {
+      reactRoot.runApplication();
+    }
     Systrace.beginAsyncSection(
       TRACE_TAG_REACT_JAVA_BRIDGE,
       "pre_rootView.onAttachedToReactInstance",

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

@@ -405,6 +405,21 @@ public class ReactRootView extends FrameLayout implements RootView, ReactRoot {
     }
   }
 
+  @Override
+  public int getWidthMeasureSpec() {
+    return mWidthMeasureSpec;
+  }
+
+  @Override
+  public int getHeightMeasureSpec() {
+    return mHeightMeasureSpec;
+  }
+
+  @Override
+  public void setShouldLogContentAppeared(boolean shouldLogContentAppeared) {
+    mShouldLogContentAppeared = shouldLogContentAppeared;
+  }
+
   private void updateRootLayoutSpecs(final int widthMeasureSpec, final int heightMeasureSpec) {
     if (mReactInstanceManager == null) {
       FLog.w(
@@ -461,7 +476,8 @@ public class ReactRootView extends FrameLayout implements RootView, ReactRoot {
     mRootViewEventListener = eventListener;
   }
 
-  /* package */ String getJSModuleName() {
+  @Override
+  public String getJSModuleName() {
     return Assertions.assertNotNull(mJSModuleName);
   }
 
@@ -506,11 +522,7 @@ public class ReactRootView extends FrameLayout implements RootView, ReactRoot {
         if (mUseSurface) {
           // TODO call surface's runApplication
         } else {
-
-          boolean isFabric = getUIManagerType() == FABRIC;
-          // Fabric requires to call updateRootLayoutSpecs before starting JS Application,
-          // this ensures the root will hace the correct pointScaleFactor.
-          if (mWasMeasured || isFabric) {
+          if (mWasMeasured) {
             updateRootLayoutSpecs(mWidthMeasureSpec, mHeightMeasureSpec);
           }
 
@@ -520,9 +532,6 @@ public class ReactRootView extends FrameLayout implements RootView, ReactRoot {
           if (appProperties != null) {
             appParams.putMap("initialProps", Arguments.fromBundle(appProperties));
           }
-          if (isFabric) {
-            appParams.putBoolean("fabric", true);
-          }
 
           mShouldLogContentAppeared = true;
 

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

@@ -39,7 +39,7 @@ public class Binding {
       ComponentFactoryDelegate componentsRegistry,
       Object reactNativeConfig);
 
-  public native void startSurface(int surfaceId, NativeMap initialProps);
+  public native void startSurface(int surfaceId, String moduleName, NativeMap initialProps);
 
   public native void renderTemplateToSurface(int surfaceId, String uiTemplate);
 

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

@@ -53,6 +53,7 @@ import com.facebook.react.fabric.mounting.mountitems.UpdateLocalDataMountItem;
 import com.facebook.react.fabric.mounting.mountitems.UpdatePropsMountItem;
 import com.facebook.react.fabric.mounting.mountitems.UpdateStateMountItem;
 import com.facebook.react.modules.core.ReactChoreographer;
+import com.facebook.react.uimanager.ReactRoot;
 import com.facebook.react.uimanager.ReactRootViewTagGenerator;
 import com.facebook.react.uimanager.StateWrapper;
 import com.facebook.react.uimanager.ThemedReactContext;
@@ -127,13 +128,18 @@ public class FabricUIManager implements UIManager, LifecycleEventListener {
 
   @Override
   public <T extends View> int addRootView(
-      final T rootView, final WritableMap initialProps, final @Nullable String initialUITemplate) {
+    final T rootView, final WritableMap initialProps, final @Nullable String initialUITemplate) {
+    return addRootView(rootView, ((ReactRoot) rootView).getJSModuleName(), initialProps, initialUITemplate);
+  }
+
+  public <T extends View> int addRootView(
+      final T rootView, final String moduleName, final WritableMap initialProps, final @Nullable String initialUITemplate) {
     final int rootTag = ReactRootViewTagGenerator.getNextRootViewTag();
     ThemedReactContext reactContext =
         new ThemedReactContext(mReactApplicationContext, rootView.getContext());
     mMountingManager.addRootView(rootTag, rootView);
     mReactContextForRootTag.put(rootTag, reactContext);
-    mBinding.startSurface(rootTag, (NativeMap) initialProps);
+    mBinding.startSurface(rootTag, moduleName, (NativeMap) initialProps);
     if (initialUITemplate != null) {
       mBinding.renderTemplateToSurface(rootTag, initialUITemplate);
     }

ReactAndroid/src/main/java/com/facebook/react/fabric/jni/Binding.cpp

@@ -45,9 +45,13 @@ jni::local_ref<Binding::jhybriddata> Binding::initHybrid(
   return makeCxxInstance();
 }
 
-void Binding::startSurface(jint surfaceId, NativeMap *initialProps) {
+void Binding::startSurface(
+    jint surfaceId,
+    jni::alias_ref<jstring> moduleName,
+    NativeMap *initialProps) {
   if (scheduler_) {
-    scheduler_->startSurface(surfaceId, "", initialProps->consume());
+    scheduler_->startSurface(
+        surfaceId, moduleName->toStdString(), initialProps->consume());
   }
 }
 

ReactAndroid/src/main/java/com/facebook/react/fabric/jni/Binding.h

@@ -50,7 +50,10 @@ class Binding : public jni::HybridClass<Binding>, public SchedulerDelegate {
       ComponentFactoryDelegate *componentsRegistry,
       jni::alias_ref<jobject> reactNativeConfig);
 
-  void startSurface(jint surfaceId, NativeMap *initialProps);
+  void startSurface(
+      jint surfaceId,
+      jni::alias_ref<jstring> moduleName,
+      NativeMap *initialProps);
 
   void renderTemplateToSurface(jint surfaceId, jstring uiTemplate);
 

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

@@ -23,6 +23,7 @@ public interface ReactRoot {
    */
   @Nullable Bundle getAppProperties();
   @Nullable String getInitialUITemplate();
+  String getJSModuleName();
 
   /**
    * Fabric or Default UI Manager, see {@link UIManagerType}
@@ -47,4 +48,15 @@ public interface ReactRoot {
    * Return native view for root
    */
   ViewGroup getRootViewGroup();
+
+  /**
+   * @return Cached values for widthMeasureSpec and heightMeasureSpec
+   */
+  int getWidthMeasureSpec();
+  int getHeightMeasureSpec();
+
+  /**
+   * Sets a flag that determines whether to log that content appeared on next view added.
+   */
+  void setShouldLogContentAppeared(boolean shouldLogContentAppeared);
 }

ReactCommon/fabric/uimanager/Scheduler.cpp

@@ -96,12 +96,10 @@ void Scheduler::startSurface(
 
   shadowTreeRegistry_.add(std::move(shadowTree));
 
-#ifndef ANDROID
   runtimeExecutor_([=](jsi::Runtime &runtime) {
     uiManagerBinding_->startSurface(
         runtime, surfaceId, moduleName, initialProps);
   });
-#endif
 }
 
 void Scheduler::renderTemplateToSurface(
@@ -171,11 +169,9 @@ void Scheduler::stopSurface(SurfaceId surfaceId) const {
   auto shadowTree = shadowTreeRegistry_.remove(surfaceId);
   shadowTree->setDelegate(nullptr);
 
-#ifndef ANDROID
   runtimeExecutor_([=](jsi::Runtime &runtime) {
     uiManagerBinding_->stopSurface(runtime, surfaceId);
   });
-#endif
 }
 
 Size Scheduler::measureSurface(