Create AndroidLibraryPlugin to share common module configuration.

First step in cleaning up duplicate code in build.gradle config files.

This CL relands ag/1746409 that had to be reverted due to not listing all the maven
repositories in buildSrc/build.gradle.

Bug: 33845666
Test: ./gradlew clean assemble assembleAndroidTest continues to work
Change-Id: I335c4366a015efa7eab880cd8d01659c41f1abb2
diff --git a/v17/preference-leanback/build.gradle b/v17/preference-leanback/build.gradle
index e58fa8b..2400168 100644
--- a/v17/preference-leanback/build.gradle
+++ b/v17/preference-leanback/build.gradle
@@ -1,4 +1,4 @@
-apply plugin: 'com.android.library'
+apply plugin: android.support.SupportLibraryPlugin
 archivesBaseName = 'preference-leanback-v17'
 
 dependencies {
@@ -13,19 +13,17 @@
 android {
     compileSdkVersion project.ext.currentSdk
 
+    defaultConfig {
+        minSdkVersion 17
+    }
+
     sourceSets {
-        main.manifest.srcFile 'AndroidManifest.xml'
         main.java.srcDirs = [
                 'api21',
                 'src'
         ]
         main.res.srcDir 'res'
     }
-
-    compileOptions {
-        sourceCompatibility JavaVersion.VERSION_1_7
-        targetCompatibility JavaVersion.VERSION_1_7
-    }
 }
 
 android.libraryVariants.all { variant ->