fix gradle compliation (#925)

Summary:
Pull Request resolved: https://github.com/facebook/yoga/pull/925

Gradle is failing to compile yoga for two reasons:
1. Ever since `YogaNodeJNIPhantomRefs` was introduced which uses `DestructorThread.Destructor` from fbjni which was the first direct Java dependency from yoga java to fbjni java code.

2. Adding a missing gradle endpoint for `testutil` since it is now required for yoga unit-tests

Reviewed By: SidharthGuglani

Differential Revision: D17274226

fbshipit-source-id: 3df9648321162d34f81fd3675ca1474e8a1c6d3a

testutil/BUCK

@@ -1,10 +1,10 @@
-load("//tools/build_defs/oss:yoga_defs.bzl", "ANDROID", "FBJNI_TARGET", "LIBRARY_COMPILER_FLAGS", "SOLOADER_TARGET", "yoga_cxx_library", "yoga_dep", "yoga_java_library")
+load("//tools/build_defs/oss:yoga_defs.bzl", "ANDROID", "FBJNI_TARGET", "LIBRARY_COMPILER_FLAGS", "SOLOADER_TARGET", "subdir_glob", "yoga_cxx_library", "yoga_dep", "yoga_java_library")
 
 yoga_cxx_library(
     name = "testutil",
-    srcs = ["testutil.cpp"],
-    header_namespace = "yoga/testutil",
-    exported_headers = ["testutil.h"],
+    srcs = ["src/main/cpp/testutil/testutil.cpp"],
+    header_namespace = "",
+    exported_headers = subdir_glob([("src/main/cpp/include", "yoga/testutil/testutil.h")]),
     compiler_flags = LIBRARY_COMPILER_FLAGS,
     soname = "libyoga_testutil.$(ext)",
     visibility = ["PUBLIC"],
@@ -13,7 +13,7 @@ yoga_cxx_library(
 
 yoga_java_library(
     name = "java",
-    srcs = ["TestUtil.java"],
+    srcs = ["src/main/java/com/facebook/yoga/TestUtil.java"],
     source = "1.7",
     target = "1.7",
     visibility = ["PUBLIC"],
@@ -25,7 +25,7 @@ yoga_java_library(
 
 yoga_cxx_library(
     name = "jni",
-    srcs = ["jni.cpp"],
+    srcs = ["src/main/cpp/jni/jni.cpp"],
     allow_jni_merging = False,
     compiler_flags = LIBRARY_COMPILER_FLAGS,
     platforms = ANDROID,

testutil/build.gradle

@@ -0,0 +1,38 @@
+/**
+ * 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.
+ */
+
+apply plugin: 'com.android.library'
+
+android {
+    compileSdkVersion rootProject.compileSdkVersion
+    buildToolsVersion rootProject.buildToolsVersion
+
+    defaultConfig {
+        minSdkVersion rootProject.minSdkVersion
+        targetSdkVersion rootProject.targetSdkVersion
+
+        ndk {
+            abiFilters 'x86', 'x86_64', 'armeabi-v7a', 'arm64-v8a'
+        }
+
+        externalNativeBuild {
+            cmake {
+                arguments '-DANDROID_TOOLCHAIN=clang', '-DANDROID_STL=c++_static'
+            }
+        }
+    }
+
+    externalNativeBuild {
+        cmake {
+            path 'src/main/cpp/CMakeLists.txt'
+        }
+    }
+
+    dependencies {
+        implementation 'com.facebook.soloader:soloader:0.5.1'
+    }
+}

testutil/src/main/AndroidManifest.xml

@@ -0,0 +1,12 @@
+<?xml version="1.0" encoding="utf-8"?>
+
+<!--
+  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.
+-->
+
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+  package="com.facebook.yoga.testutil">
+</manifest>

testutil/src/main/cpp/CMakeLists.txt

@@ -0,0 +1,30 @@
+#
+# 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.
+#
+
+cmake_minimum_required(VERSION 3.4.1)
+
+set(CMAKE_VERBOSE_MAKEFILE on)
+
+add_compile_options(
+    -fno-omit-frame-pointer
+    -fexceptions
+    -Wall
+    -std=c++11
+    -DDISABLE_CPUCAP
+    -DDISABLE_XPLAT)
+
+file(GLOB testutil_SRC
+    jni/*.cpp
+    testutil/*.cpp)
+
+add_library(testutil SHARED
+    ${testutil_SRC})
+
+target_include_directories(testutil PRIVATE
+    include)
+
+target_link_libraries(testutil android log)

testutil/src/main/cpp/testutil/testutil.cpp

@@ -4,7 +4,7 @@
  * This source code is licensed under the MIT license found in the LICENSE
  * file in the root directory of this source tree.
  */
-#include "testutil.h"
+#include <yoga/testutil/testutil.h>
 
 #include <yoga/YGNode.h>
 #include <yoga/event/event.h>