Facebook SDK 추가 후 Android 빌드 시 Duplicated class 오류 해결

Facebook SDK 연동 후 다음과 같은 오류가 계속 발생하면서 빌드 Failed가 떴다.

> 1 exception was raised by workers:
  java.lang.RuntimeException: Duplicate class android.support.customtabs.ICustomTabsCallback found in modules classes.jar (androidx.browser:browser:1.0.0) and classes.jar (com.android.support:customtabs:25.3.1)
  Duplicate class android.support.customtabs.ICustomTabsCallback$Stub found in modules classes.jar (androidx.browser:browser:1.0.0) and classes.jar (com.android.support:customtabs:25.3.1)
  Duplicate class android.support.customtabs.ICustomTabsCallback$Stub$Proxy found in modules classes.jar (androidx.browser:browser:1.0.0) and classes.jar (com.android.support:customtabs:25.3.1)
  Duplicate class android.support.customtabs.ICustomTabsService found in modules classes.jar (androidx.browser:browser:1.0.0) and classes.jar (com.android.support:customtabs:25.3.1)
  Duplicate class android.support.customtabs.ICustomTabsService$Stub found in modules classes.jar (androidx.browser:browser:1.0.0) and classes.jar (com.android.support:customtabs:25.3.1)
  Duplicate class android.support.customtabs.ICustomTabsService$Stub$Proxy found in modules classes.jar (androidx.browser:browser:1.0.0) and classes.jar (com.android.support:customtabs:25.3.1)
  Duplicate class android.support.customtabs.IPostMessageService found in modules classes.jar (androidx.browser:browser:1.0.0) and classes.jar (com.android.support:customtabs:25.3.1)
  Duplicate class android.support.customtabs.IPostMessageService$Stub found in modules classes.jar (androidx.browser:browser:1.0.0) and classes.jar (com.android.support:customtabs:25.3.1)
  Duplicate class android.support.customtabs.IPostMessageService$Stub$Proxy found in modules classes.jar (androidx.browser:browser:1.0.0) and classes.jar (com.android.support:customtabs:25.3.1)
....

해결방법은 의외로 간단하다.

(1) Unity > Edit > Project Setting > Player

아래 이미지에서 Customg Gradle Properties Template 체크

(2) Unity 프로젝트 폴더 하위 Assets > Plugins > Android > gradleTemplate.properties 파일 오픈

오픈하면 이런식으로 되어 있음

org.gradle.jvmargs=-Xmx**JVM_HEAP_SIZE**M
org.gradle.parallel=true
**ADDITIONAL_PROPERTIES**

**ADDITIONAL_PROPERTIES** 위에 아래 두줄 추가

android.useAndroidX=true
android.enableJetifier=true

최종 gradleTemplate.properties 파일은 아래와 같이 된다.

org.gradle.jvmargs=-Xmx**JVM_HEAP_SIZE**M
org.gradle.parallel=true
android.useAndroidX=true
android.enableJetifier=true
**ADDITIONAL_PROPERTIES**

이렇게 한 후 빌드하면 오류가 사라지고 빌드에 성공한다.