WorkflowLayout now relies on Lifecycle.

Our homegrown `View.takeWhileAttached` somehow causes a strange issue on API
30 devices where `View.onAttached` can be called twice, at least since the
recent change to introduce `View.start` landed in #602. We've seen crashes on
a variety of Samsung devices out in the wild, and can reproduce the issue on
API 30 AVDs via Android Studio's _Apply Changes and Restart Activity_.

The fix is to be mainstream and use `Lifecycle`, which add as a new required
parameter to `WorkflowLayout.start`. The old overloads are now deprecated,
and will be deleted soon.

Author: rjrjr

samples/hello-workflow/src/main/java/com/squareup/sample/helloworkflow/HelloWorkflowActivity.kt

@@ -21,7 +21,7 @@ class HelloWorkflowActivity : AppCompatActivity() {
     // succeeding calls.
     val model: HelloViewModel by viewModels()
     setContentView(
-      WorkflowLayout(this).apply { start(model.renderings) }
+      WorkflowLayout(this).also { contentView -> contentView.start(lifecycle, model.renderings) }
     )
   }
 }

workflow-ui/core-android/api/core-android.api

@@ -132,8 +132,11 @@ public abstract interface class com/squareup/workflow1/ui/ViewStarter {
 public final class com/squareup/workflow1/ui/WorkflowLayout : android/widget/FrameLayout {
 	public fun <init> (Landroid/content/Context;Landroid/util/AttributeSet;)V
 	public synthetic fun <init> (Landroid/content/Context;Landroid/util/AttributeSet;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
+	public final fun start (Landroidx/lifecycle/Lifecycle;Lkotlinx/coroutines/flow/Flow;Lcom/squareup/workflow1/ui/ViewEnvironment;)V
+	public final fun start (Landroidx/lifecycle/Lifecycle;Lkotlinx/coroutines/flow/Flow;Lcom/squareup/workflow1/ui/ViewRegistry;)V
 	public final fun start (Lkotlinx/coroutines/flow/Flow;Lcom/squareup/workflow1/ui/ViewEnvironment;)V
 	public final fun start (Lkotlinx/coroutines/flow/Flow;Lcom/squareup/workflow1/ui/ViewRegistry;)V
+	public static synthetic fun start$default (Lcom/squareup/workflow1/ui/WorkflowLayout;Landroidx/lifecycle/Lifecycle;Lkotlinx/coroutines/flow/Flow;Lcom/squareup/workflow1/ui/ViewEnvironment;ILjava/lang/Object;)V
 	public static synthetic fun start$default (Lcom/squareup/workflow1/ui/WorkflowLayout;Lkotlinx/coroutines/flow/Flow;Lcom/squareup/workflow1/ui/ViewEnvironment;ILjava/lang/Object;)V
 }
 

workflow-ui/core-android/src/main/java/com/squareup/workflow1/ui/WorkflowLayout.kt

@@ -10,10 +10,13 @@ import android.view.View
 import android.view.ViewGroup
 import android.view.ViewGroup.LayoutParams.MATCH_PARENT
 import android.widget.FrameLayout
+import androidx.lifecycle.Lifecycle
+import androidx.lifecycle.coroutineScope
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.Job
 import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.collect
 import kotlinx.coroutines.flow.launchIn
 import kotlinx.coroutines.flow.onEach
 
@@ -43,28 +46,51 @@ public class WorkflowLayout(
 
   private var restoredChildState: SparseArray<Parcelable>? = null
 
+  @Suppress("DeprecatedCallableAddReplaceWith")
+  @Deprecated("Provide an androidx Lifecyle")
+  public fun start(
+    renderings: Flow<Any>,
+    registry: ViewRegistry
+  ) {
+    @Suppress("DEPRECATION")
+    start(renderings, ViewEnvironment(mapOf(ViewRegistry to registry)))
+  }
+
   /**
    * Subscribes to [renderings], and uses [registry] to
    * [build a new view][ViewRegistry.buildView] each time a new type of rendering is received,
    * making that view the only child of this one.
    */
   public fun start(
+    lifecycle: Lifecycle,
     renderings: Flow<Any>,
     registry: ViewRegistry
   ) {
-    start(renderings, ViewEnvironment(mapOf(ViewRegistry to registry)))
+    start(lifecycle, renderings, ViewEnvironment(mapOf(ViewRegistry to registry)))
   }
 
+  @Deprecated("Provide an androidx Lifecyle")
+  public fun start(
+    renderings: Flow<Any>,
+    environment: ViewEnvironment = ViewEnvironment()
+  ) {
+    takeWhileAttachedIfYouAreAnIdiotNoDoNotUseThis(renderings) { show(it, environment) }
+  }
+
+
   /**
    * Subscribes to [renderings], and uses the [ViewRegistry] in the given [environment] to
    * [build a new view][ViewRegistry.buildView] each time a new type of rendering is received,
    * making that view the only child of this one.
    */
   public fun start(
+    lifecycle: Lifecycle,
     renderings: Flow<Any>,
     environment: ViewEnvironment = ViewEnvironment()
   ) {
-    takeWhileAttached(renderings) { show(it, environment) }
+    lifecycle.coroutineScope.launchWhenStarted {
+      renderings.collect { show(it, environment) }
+    }
   }
 
   private fun show(
@@ -131,7 +157,7 @@ public class WorkflowLayout(
   /**
    * Subscribes [update] to [source] only while this [View] is attached to a window.
    */
-  private fun <S : Any> View.takeWhileAttached(
+  private fun <S : Any> View.takeWhileAttachedIfYouAreAnIdiotNoDoNotUseThis(
     source: Flow<S>,
     update: (S) -> Unit
   ) {