Update library versions. (#414)

Removes buildToolsVersions because an appropriate version is picked

build.gradle

@@ -21,12 +21,11 @@ buildscript {
         minSdkVersion = 14
         targetSdkVersion = 27
         compileSdkVersion = 27
-        buildToolsVersion = "27.0.2"
         androidGradlePluginVersion = "3.0.1"
         androidMavenGradlePluginVersion = "1.5"
         gradleBintrayPluginVersion = "1.6"
-        kotlinVersion = "1.2.0"
-        supportLibVersion = "27.0.2"
+        kotlinVersion = "1.2.30"
+        supportLibVersion = "27.1.0"
         espressoVersion = "3.0.0"
         testRunnerVersion = "1.0.0"
         junitVersion = "4.12"

demo-cat-gallery/build.gradle

@@ -19,7 +19,6 @@ apply plugin: 'kotlin-android'
 
 android {
     compileSdkVersion rootProject.ext.compileSdkVersion
-    buildToolsVersion rootProject.ext.buildToolsVersion
 
     defaultConfig {
         applicationId "com.google.android.flexbox.apps.catgallery"

demo-playground/build.gradle

@@ -19,7 +19,6 @@ apply plugin: 'kotlin-android'
 
 android {
     compileSdkVersion rootProject.ext.compileSdkVersion
-    buildToolsVersion rootProject.ext.buildToolsVersion
 
     defaultConfig {
         applicationId "com.google.android.apps.flexbox"

flexbox/build.gradle

@@ -21,7 +21,6 @@ apply from: 'bintray.gradle'
 
 android {
     compileSdkVersion rootProject.ext.compileSdkVersion
-    buildToolsVersion rootProject.ext.buildToolsVersion
 
     defaultConfig {
         minSdkVersion rootProject.ext.minSdkVersion

flexbox/src/androidTest/java/com/google/android/flexbox/test/TestAdapter.kt

@@ -25,7 +25,9 @@ import com.google.android.flexbox.FlexboxLayoutManager
 /**
  * [RecyclerView.Adapter] implementation for [TestViewHolder].
  */
-internal class TestAdapter private constructor(private val layoutParams: MutableList<FlexboxLayoutManager.LayoutParams>) : RecyclerView.Adapter<TestViewHolder>() {
+internal class TestAdapter private constructor(
+        private val layoutParams: MutableList<FlexboxLayoutManager.LayoutParams>)
+    : RecyclerView.Adapter<TestViewHolder>() {
 
     private val receivedPayloads = mutableListOf<Any>()
 
@@ -44,8 +46,8 @@ internal class TestAdapter private constructor(private val layoutParams: Mutable
         holder.textView.layoutParams = layoutParams[position]
     }
 
-    override fun onBindViewHolder(holder: TestViewHolder, position: Int, payloads: List<Any>?) {
-        payloads?.let(receivedPayloads::addAll)
+    override fun onBindViewHolder(holder: TestViewHolder, position: Int, payloads: List<Any>) {
+        receivedPayloads.addAll(payloads)
         onBindViewHolder(holder, position)
     }