Use SupervisorJob in viewModelscope

Test: testJobIsSuperVisor
Change-Id: I473e3e901d1aec9cac5a42f18b7c70793aa6c1d0

diff --git a/lifecycle/viewmodel/ktx/src/androidTest/java/androidx/lifecycle/ViewModelTest.kt b/lifecycle/viewmodel/ktx/src/androidTest/java/androidx/lifecycle/ViewModelTest.kt
index 127afe77..a5e4553 100644
--- a/lifecycle/viewmodel/ktx/src/androidTest/java/androidx/lifecycle/ViewModelTest.kt
+++ b/lifecycle/viewmodel/ktx/src/androidTest/java/androidx/lifecycle/ViewModelTest.kt

@@ -18,8 +18,12 @@
 
 import androidx.test.filters.SmallTest
 import com.google.common.truth.Truth
+import kotlinx.coroutines.async
+import kotlinx.coroutines.cancelAndJoin
 import kotlinx.coroutines.delay
 import kotlinx.coroutines.launch
+import kotlinx.coroutines.runBlocking
+import org.junit.Assert
 import org.junit.Test
 import org.junit.runner.RunWith
 import org.junit.runners.JUnit4
@@ -53,4 +57,21 @@
         val scope3 = vm.viewModelScope
         Truth.assertThat(scope3).isSameAs(scope2)
     }
+
+    @Test fun testJobIsSuperVisor() {
+        val vm = object : ViewModel() {}
+        val scope = vm.viewModelScope
+        val delayingDeferred = scope.async { delay(Long.MAX_VALUE) }
+        val failingDeferred = scope.async { throw Error() }
+
+        runBlocking {
+            try {
+                failingDeferred.await()
+                Assert.fail()
+            } catch (e: Error) {
+            }
+            Truth.assertThat(delayingDeferred.isActive).isTrue()
+            delayingDeferred.cancelAndJoin()
+        }
+    }
 }
\ No newline at end of file

diff --git a/lifecycle/viewmodel/ktx/src/main/java/androidx/lifecycle/ViewModel.kt b/lifecycle/viewmodel/ktx/src/main/java/androidx/lifecycle/ViewModel.kt
index 74a0f00..0d8e203 100644
--- a/lifecycle/viewmodel/ktx/src/main/java/androidx/lifecycle/ViewModel.kt
+++ b/lifecycle/viewmodel/ktx/src/main/java/androidx/lifecycle/ViewModel.kt

@@ -18,7 +18,7 @@
 
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Dispatchers
-import kotlinx.coroutines.Job
+import kotlinx.coroutines.SupervisorJob
 import kotlinx.coroutines.cancel
 import java.io.Closeable
 import kotlin.coroutines.CoroutineContext
@@ -38,7 +38,7 @@
                 return scope
             }
             return setTagIfAbsent(JOB_KEY,
-                CloseableCoroutineScope(Job() + Dispatchers.Main))
+                CloseableCoroutineScope(SupervisorJob() + Dispatchers.Main))
         }
 
 internal class CloseableCoroutineScope(context: CoroutineContext) : Closeable, CoroutineScope {