title: webrtc native API 'vectorDrawable' & 'Task' error when sync build.grandle
body: <p>First at all: I copy and paste these question from my 'off topic' post into android enthusiast. Someone suggest me to ask here for these.</p>
  
  <p>I try to install on my lollipop device AppRTCMobile example containing on official repo.</p>
  
  <p>i find  a first little error on grandle.build file (not closing 
  "}").Actually I obtain these error on my log file:</p>
  
  <pre><code>WARN - ect.sync.idea.ProjectSetUpTask - Could not get unknown property     
  
      'vectorDrawables' for source set default config of type com.android.build.gradle.internal.api.DefaultAndroidSourceSet.
  
  Consult IDE log for more details (Help | Show Log) 
  2018-02-13 13:07:01,478 [d thread 6]   INFO - e.project.sync.GradleSyncState - Gradle sync failed: Could not get unknown  property 'vectorDrawables' for source set default config of type com.android.build.gradle.internal.api.DefaultAndroidSourceSet.
  </code></pre>
  
  <p>my build.grandle result these:</p>
  
  <pre><code>// Generated by //build/android/generate_gradle.py
  
  buildscript {
      repositories {
          jcenter()
          maven {
              url 'https://maven.google.com'
          }
      }
      dependencies {
          classpath "com.android.tools.build:gradle:3.1.0-alpha08"
      } }
  </code></pre>
  
  <p>and my example AppRTCMobile build.grandle result these:</p>
  
  <pre><code>// Generated by //build/android/generate_gradle.py
  
  apply plugin: "com.android.application"
  
  android {
      compileSdkVersion "android-27"
      buildToolsVersion "27.0.1"
  
  compileOptions {
      sourceCompatibility JavaVersion.VERSION_1_8
      targetCompatibility JavaVersion.VERSION_1_8
  }
  
  sourceSets {
      main {
          aidl.srcDirs = []
          assets.srcDirs = []
          java.srcDirs = []
          jni.srcDirs = []
          renderscript.srcDirs = []
          res.srcDirs = []
          resources.srcDirs = []
      }
      test {
          aidl.srcDirs = []
          assets.srcDirs = []
          java.srcDirs = []
          jni.srcDirs = []
          renderscript.srcDirs = []
          res.srcDirs = []
          resources.srcDirs = []
      }
      androidTest {
          aidl.srcDirs = []
          assets.srcDirs = []
          java.srcDirs = []
          jni.srcDirs = []
          renderscript.srcDirs = []
          res.srcDirs = []
          resources.srcDirs = []
      }
      debug {
          aidl.srcDirs = []
          assets.srcDirs = []
          java.srcDirs = []
          jni.srcDirs = []
          renderscript.srcDirs = []
          res.srcDirs = []
          resources.srcDirs = []
      }
      release {
          aidl.srcDirs = []
          assets.srcDirs = []
          java.srcDirs = []
          jni.srcDirs = []
          renderscript.srcDirs = []
          res.srcDirs = []
          resources.srcDirs = []
      }
  
      main {
          manifest.srcFile "../../../../../examples/androidapp/AndroidManifest.xml"
          java.srcDirs = [
              "extracted-srcjars",
          ]
          java.filter.exclude(
          )
          jniLibs.srcDirs = [
              "symlinked-libs",
          ]
          res.srcDirs = [
              "extracted-res",
          ]
      }
  
  
  
  
      defaultConfig {
          vectorDrawables.useSupportLibrary = true
      } }
  
  
  dependencies {
      implementation project(path: ":examples.AppRTCMobile_javalib")
      implementation project(path: ":rtc_base.base_java")
      implementation project(path: ":base.base_java")
  
  
  
  } afterEvaluate {
      def tasksToDisable = tasks.findAll {
          return (it.name.equals('generateDebugSources')  // causes unwanted AndroidManifest.java
                  || it.name.equals('generateReleaseSources')
                  || it.name.endsWith('BuildConfig')  // causes unwanted BuildConfig.java
                  || it.name.equals('preDebugAndroidTestBuild')
                  || it.name.endsWith('Aidl')
                  || it.name.endsWith('Renderscript')
                  || it.name.endsWith('Shaders'))
      }
      tasksToDisable.each { Task task -&gt;
        task.enabled = false
      } }
  </code></pre>
  
  <p>Why I got these error? My buld.grandle on AppRTCMobile is wrong or contain some error??</p>
  
  <p>UPDATE:</p>
  
  <p>I try to clear project and import only AppRTCMobile example .... multiple error only about vectorDrawable: 
  choice 1) comment out "vectorDrawables.useSupportLibrary = true" line in every build file of project. 
  Choice 2) utilize the right library (more than 23.x) and set min support sdk api to 21 instead 16. </p>
  
  <p>I use chose 1). result these error: </p>
  
  <pre><code>/home/myoffice/chromium/src/out/DebugArm/gradle/examples/AppRTCMobile/build/generated/source/r/debug/org/appspot/apprtc/R.java
  Error:(10, 14) error: duplicate class: org.appspot.apprtc.R
  </code></pre>
  
  <p>obviusly refactor that class not work. These error type where came from?</p>
  
  <p>regards
  bkt</p>