RNTester Android: Add stub C++ for TurboModule provider

.gitignore

@@ -25,6 +25,7 @@ project.xcworkspace
 /build/
 /packages/react-native-codegen/android/build/
 /packages/react-native-codegen/android/gradlePlugin-build/gradlePlugin/build
+/packages/rn-tester/android/app/.cxx/
 /packages/rn-tester/android/app/build/
 /packages/rn-tester/android/app/gradle/
 /packages/rn-tester/android/app/gradlew

packages/rn-tester/android/app/build.gradle

@@ -85,6 +85,7 @@ project.ext.react = [
     hermesCommand: "$rootDir/node_modules/hermes-engine/%OS-BIN%/hermesc",
     enableHermesForVariant: { def v -> v.name.contains("hermes") },
     jsRootDir: "$rootDir/RNTester",
+    enableCodegen: (System.getenv('USE_CODEGEN') ?: '0').toBoolean(),
     enableFabric: (System.getenv('USE_FABRIC') ?: '0').toBoolean(),
 ]
 
@@ -106,6 +107,11 @@ def enableSeparateBuildPerCPUArchitecture = true
  */
 def enableProguardInReleaseBuilds = true
 
+/**
+ * Build and enable codegen-related output in RN Tester app.
+ */
+def enableCodegen = project.ext.react.enableCodegen
+
 /**
  * Build and enable Fabric in RN Tester app.
  */
@@ -179,6 +185,29 @@ android {
     }
 }
 
+if (enableCodegen) {
+    android {
+        defaultConfig {
+            externalNativeBuild {
+                ndkBuild {
+                    abiFilters "armeabi-v7a", "x86", "x86_64", "arm64-v8a"
+                    arguments "APP_PLATFORM=android-16",
+                            "APP_STL=c++_shared",
+                            "NDK_TOOLCHAIN_VERSION=clang"
+                    cFlags "-Wall", "-Werror", "-fexceptions", "-frtti", "-DWITH_INSPECTOR=1"
+                    cppFlags "-std=c++1y"
+                    targets "rntester_appmodules"
+                }
+            }
+        }
+        externalNativeBuild {
+            ndkBuild {
+                path "$projectDir/src/main/jni/Android.mk"
+            }
+        }
+    }
+}
+
 configurations {
   hermesDebugImplementation {}
   hermesReleaseImplementation {}

packages/rn-tester/android/app/src/main/jni/Android.mk

@@ -0,0 +1,29 @@
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+LOCAL_PATH := $(call my-dir)
+
+include $(CLEAR_VARS)
+
+LOCAL_MODULE := rntester_appmodules
+
+LOCAL_C_INCLUDES := $(LOCAL_PATH)
+
+LOCAL_SRC_FILES := $(wildcard $(LOCAL_PATH)/*.cpp)
+
+LOCAL_EXPORT_C_INCLUDES := $(LOCAL_PATH)
+
+# TODO
+# LOCAL_SHARED_LIBRARIES := libreact_nativemodule_core libreactnativejni
+
+# TODO
+# LOCAL_STATIC_LIBRARIES := libjsi
+
+LOCAL_CFLAGS := \
+  -DLOG_TAG=\"ReactNative\"
+
+LOCAL_CFLAGS += -fexceptions -frtti -std=c++14 -Wall
+
+include $(BUILD_SHARED_LIBRARY)

packages/rn-tester/android/app/src/main/jni/RNTesterAppModuleProvider.cpp

@@ -0,0 +1,18 @@
+/*
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#include "RNTesterAppModuleProvider.h"
+
+namespace facebook {
+namespace react {
+
+std::shared_ptr<void> RNTesterAppModuleProvider(const std::string moduleName) {
+  return nullptr;
+}
+
+} // namespace react
+} // namespace facebook

packages/rn-tester/android/app/src/main/jni/RNTesterAppModuleProvider.h

@@ -0,0 +1,19 @@
+/*
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#pragma once
+
+#include <memory>
+#include <string>
+
+namespace facebook {
+namespace react {
+
+std::shared_ptr<void> RNTesterAppModuleProvider(const std::string moduleName);
+
+} // namespace react
+} // namespace facebook