Prepare scenario app to run on Android emulator on LUCI (#20350)

testing/scenario_app/android/app/src/androidTest/java/dev/flutter/scenariosui/ScreenshotUtil.java

@@ -13,7 +13,6 @@ import android.os.Looper;
 import android.util.Xml;
 import androidx.test.InstrumentationRegistry;
 import androidx.test.runner.AndroidJUnitRunner;
-import androidx.test.runner.screenshot.Screenshot;
 import com.facebook.testing.screenshot.ScreenshotRunner;
 import com.facebook.testing.screenshot.internal.AlbumImpl;
 import com.facebook.testing.screenshot.internal.Registry;
@@ -164,8 +163,6 @@ public class ScreenshotUtil {
 
     // This method is called from the runner thread,
     // so block the UI thread while taking the screenshot.
-    // UiThreadLocker locker = new UiThreadLocker();
-    // locker.lock();
 
     // Screenshot.capture(view or activity) does not capture the Flutter UI.
     // Unfortunately, it doesn't work with Android's `Surface` or `TextureSurface`.
@@ -182,7 +179,8 @@ public class ScreenshotUtil {
         new Callable<Void>() {
           @Override
           public Void call() {
-            Bitmap bitmap = Screenshot.capture().getBitmap();
+            Bitmap bitmap =
+                InstrumentationRegistry.getInstrumentation().getUiAutomation().takeScreenshot();
             // Remove the status and action bars from the screenshot capture.
             bitmap =
                 Bitmap.createBitmap(

testing/scenario_app/android/app/src/main/java/dev/flutter/scenarios/TestableFlutterActivity.java

@@ -4,27 +4,34 @@
 
 package dev.flutter.scenarios;
 
-import android.os.Bundle;
 import io.flutter.embedding.android.FlutterActivity;
+import io.flutter.embedding.engine.FlutterEngine;
+import java.util.concurrent.atomic.AtomicBoolean;
 
 public class TestableFlutterActivity extends FlutterActivity {
-  private Object flutterUiRenderedLock;
+  private Object flutterUiRenderedLock = new Object();
+  private AtomicBoolean isScenarioReady = new AtomicBoolean(false);
 
   @Override
-  protected void onCreate(Bundle savedInstanceState) {
-    super.onCreate(savedInstanceState);
-    // Reset the lock.
-    flutterUiRenderedLock = new Object();
+  public void configureFlutterEngine(FlutterEngine flutterEngine) {
+    super.configureFlutterEngine(flutterEngine);
+    flutterEngine
+        .getDartExecutor()
+        .setMessageHandler("take_screenshot", (byteBuffer, binaryReply) -> notifyFlutterRendered());
   }
 
   protected void notifyFlutterRendered() {
     synchronized (flutterUiRenderedLock) {
+      isScenarioReady.set(true);
       flutterUiRenderedLock.notifyAll();
     }
   }
 
   public void waitUntilFlutterRendered() {
     try {
+      if (isScenarioReady.get()) {
+        return;
+      }
       synchronized (flutterUiRenderedLock) {
         flutterUiRenderedLock.wait();
       }

testing/scenario_app/android/app/src/main/java/dev/flutter/scenarios/TextPlatformViewActivity.java

@@ -12,7 +12,6 @@ import android.os.Build;
 import android.os.Bundle;
 import android.os.Handler;
 import android.os.Looper;
-import android.view.Choreographer;
 import androidx.annotation.NonNull;
 import io.flutter.Log;
 import io.flutter.embedding.engine.FlutterEngine;
@@ -71,6 +70,7 @@ public class TextPlatformViewActivity extends TestableFlutterActivity {
 
   @Override
   public void configureFlutterEngine(FlutterEngine flutterEngine) {
+    super.configureFlutterEngine(flutterEngine);
     flutterEngine
         .getPlatformViewsController()
         .getRegistry()
@@ -89,22 +89,6 @@ public class TextPlatformViewActivity extends TestableFlutterActivity {
     test.put("name", launchIntent.getStringExtra("scenario"));
     test.put("use_android_view", launchIntent.getBooleanExtra("use_android_view", false));
     channel.invokeMethod("set_scenario", test);
-
-    notifyFlutterRenderedAfterVsync();
-  }
-
-  private void notifyFlutterRenderedAfterVsync() {
-    // Wait 1s after the next frame, so the Android texture are rendered.
-    Choreographer.getInstance()
-        .postFrameCallbackDelayed(
-            new Choreographer.FrameCallback() {
-              @Override
-              public void doFrame(long frameTimeNanos) {
-                reportFullyDrawn();
-                notifyFlutterRendered();
-              }
-            },
-            1000L);
   }
 
   private void writeTimelineData(Uri logFile) {

testing/scenario_app/build_and_run_android_tests.sh

-#!/bin/sh
+#!/bin/bash
 # Copyright 2013 The Flutter Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.

testing/scenario_app/compile_android_jit.sh

@@ -28,6 +28,16 @@ echo "Using dart from $HOST_TOOLS, gen_snapshot from $DEVICE_TOOLS."
 OUTDIR="${BASH_SOURCE%/*}/build/app"
 FLUTTER_ASSETS_DIR=$OUTDIR/assets/flutter_assets
 LIBS_DIR="${BASH_SOURCE%/*}/android/app/libs"
+GEN_SNAPSHOT=$DEVICE_TOOLS/gen_snapshot
+
+if [[ ! -f "$GEN_SNAPSHOT" ]]; then
+  GEN_SNAPSHOT=$DEVICE_TOOLS/gen_snapshot_host_targeting_host
+fi
+
+if [[ ! -f "$GEN_SNAPSHOT" ]]; then
+  echo "Could not find gen_snapshot in $DEVICE_TOOLS."
+  exit 1
+fi
 
 echo "Creating directories..."
 
@@ -47,7 +57,7 @@ echo "Compiling kernel..."
 
 echo "Compiling JIT Snapshot..."
 
-"$DEVICE_TOOLS/gen_snapshot" --deterministic \
+"$GEN_SNAPSHOT" --deterministic \
   --enable-asserts \
   --no-causal_async_stacks \
   --lazy_async_stacks \

testing/scenario_app/lib/main.dart

@@ -90,6 +90,14 @@ Future<Map<String, dynamic>> _getJson(Uri uri) async {
 
 void _onBeginFrame(Duration duration) {
   currentScenario?.onBeginFrame(duration);
+
+  // Render an empty frame to signal first frame in the platform side.
+  if (currentScenario == null) {
+    final SceneBuilder builder = SceneBuilder();
+    final Scene scene = builder.build();
+    window.render(scene);
+    scene.dispose();
+  }
 }
 
 void _onDrawFrame() {

testing/scenario_app/lib/src/scenario.dart

@@ -9,11 +9,14 @@ import 'dart:ui';
 /// A scenario to run for testing.
 abstract class Scenario {
   /// Creates a new scenario using a specific Window instance.
-  const Scenario(this.window);
+  Scenario(this.window);
 
   /// The window used by this scenario. May be mocked.
   final Window window;
 
+  /// [true] if a screenshot is taken in the next frame.
+  bool _didScheduleScreenshot = false;
+
   /// Called by the program when a frame is ready to be drawn.
   ///
   /// See [Window.onBeginFrame] for more details.
@@ -23,7 +26,22 @@ abstract class Scenario {
   /// flushed.
   ///
   /// See [Window.onDrawFrame] for more details.
-  void onDrawFrame() {}
+  void onDrawFrame() {
+    Future<void>.delayed(const Duration(seconds: 1), () {
+      if (_didScheduleScreenshot) {
+        window.sendPlatformMessage('take_screenshot', null, null);
+      } else {
+        _didScheduleScreenshot = true;
+        window.scheduleFrame();
+      }
+    });
+  }
+
+  /// Called when the current scenario has been unmount due to a
+  /// new scenario being mount.
+  void unmount() {
+    _didScheduleScreenshot = false;
+  }
 
   /// Called by the program when the window metrics have changed.
   ///

testing/scenario_app/lib/src/scenarios.dart

@@ -43,11 +43,9 @@ Map<String, ScenarioFactory> _scenarios = <String, ScenarioFactory>{
   'text_semantics_focus': () => SendTextFocusScemantics(window),
 };
 
-Map<String, dynamic> _currentScenarioParams = <String, dynamic>{
-  'name': 'animated_color_square',
-};
+Map<String, dynamic> _currentScenarioParams = <String, dynamic>{};
 
-Scenario _currentScenarioInstance = _scenarios[_currentScenarioParams['name']]();
+Scenario _currentScenarioInstance;
 
 /// Loads an scenario.
 /// The map must contain a `name` entry, which equals to the name of the scenario.
@@ -55,6 +53,11 @@ void loadScenario(Map<String, dynamic> scenario) {
   final String scenarioName = scenario['name'] as String;
   assert(_scenarios[scenarioName] != null);
   _currentScenarioParams = scenario;
+
+  if (_currentScenarioInstance != null) {
+    _currentScenarioInstance.unmount();
+  }
+
   _currentScenarioInstance = _scenarios[scenario['name']]();
   window.scheduleFrame();
   print('Loading scenario $scenarioName');

testing/scenario_app/run_android_tests.sh

-#!/bin/sh
+#!/bin/bash
 # Copyright 2013 The Flutter Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.