Ensure compatibility for Firebase and Google Play Services

android/build.gradle

@@ -1,5 +1,8 @@
 apply plugin: 'com.android.library'
 
+def DEFAULT_GOOGLE_PLAY_SERVICES_VERSION = "11.8.+";
+def DEFAULT_FIREBASE_CORE_VERSION = "11.8.+";
+
 android {
   compileSdkVersion 26
   buildToolsVersion '26.0.2'
@@ -23,12 +26,20 @@ android {
 }
 
 dependencies {
+  def googlePlayServicesVersion = project.hasProperty('googlePlayServicesVersion')
+    ? project.googlePlayServicesVersion
+    : DEFAULT_GOOGLE_PLAY_SERVICES_VERSION
+
+  def firebaseCoreVersion = project.hasProperty('firebaseCoreVersion')
+    ? project.firebaseCoreVersion
+    : DEFAULT_FIREBASE_CORE_VERSION
+
   compile fileTree(include: ['*.jar'], dir: 'libs')
   compile 'com.facebook.react:react-native:+'
   compile 'com.android.support:support-v4:26.1.0'
   compile 'com.android.support:appcompat-v7:26.1.0'
-  compile 'com.google.android.gms:play-services-wallet:11.8.0'
-  compile 'com.google.firebase:firebase-core:11.8.0'
+  compile "com.google.android.gms:play-services-wallet:$googlePlayServicesVersion"
+  compile "com.google.firebase:firebase-core:$firebaseCoreVersion"
   compile 'com.stripe:stripe-android:6.0.0'
   compile 'com.github.tipsi:CreditCardEntry:1.4.8.10'
 }

example/android/app/build.gradle

@@ -89,6 +89,9 @@ def enableSeparateBuildPerCPUArchitecture = false
  */
 def enableProguardInReleaseBuilds = false
 
+def googlePlayServicesVersion = project.googlePlayServicesVersion
+def firebaseCoreVersion = project.firebaseCoreVersion
+
 android {
     compileSdkVersion 26
     buildToolsVersion "26.0.2"

example/android/gradle.properties

@@ -19,3 +19,5 @@
 
 android.useDeprecatedNdk=true
 android.enableAapt2=false
+googlePlayServicesVersion=15.0.1
+firebaseCoreVersion=16.0.0