Multiview: Add view ID to _render and remove render rule skipping

lib/ui/dart_ui.cc

@@ -98,7 +98,7 @@ typedef CanvasPath Path;
   V(NativeStringAttribute::initSpellOutStringAttribute, 3)            \
   V(PlatformConfigurationNativeApi::DefaultRouteName, 0)              \
   V(PlatformConfigurationNativeApi::ScheduleFrame, 0)                 \
-  V(PlatformConfigurationNativeApi::Render, 1)                        \
+  V(PlatformConfigurationNativeApi::Render, 4)                        \
   V(PlatformConfigurationNativeApi::UpdateSemantics, 1)               \
   V(PlatformConfigurationNativeApi::SetNeedsReportTimings, 1)         \
   V(PlatformConfigurationNativeApi::SetIsolateDebugName, 1)           \

lib/ui/platform_dispatcher.dart

@@ -308,29 +308,6 @@ class PlatformDispatcher {
     _invoke(onMetricsChanged, _onMetricsChangedZone);
   }
 
-  // A debug-only variable that stores the [FlutterView]s for which
-  // [FlutterView.render] has already been called during the current
-  // [onBeginFrame]/[onDrawFrame] callback sequence.
-  //
-  // It is null outside the scope of those callbacks indicating that calls to
-  // [FlutterView.render] must be ignored. Furthermore, if a given [FlutterView]
-  // is already present in this set when its [FlutterView.render] is called
-  // again, that call must be ignored as a duplicate.
-  //
-  // Between [onBeginFrame] and [onDrawFrame] the properties value is
-  // temporarily stored in `_renderedViewsBetweenCallbacks` so that it survives
-  // the gap between the two callbacks.
-  //
-  // In release build, this variable is null, and therefore the calling rule is
-  // not enforced. This is because the check might hurt cold startup delay;
-  // see https://github.com/flutter/engine/pull/46919.
-  Set<FlutterView>? _debugRenderedViews;
-  // A debug-only variable that temporarily stores the `_renderedViews` value
-  // between `_beginFrame` and `_drawFrame`.
-  //
-  // In release build, this variable is null.
-  Set<FlutterView>? _debugRenderedViewsBetweenCallbacks;
-
   /// A callback invoked when any view begins a frame.
   ///
   /// A callback that is invoked to notify the application that it is an
@@ -351,26 +328,11 @@ class PlatformDispatcher {
 
   // Called from the engine, via hooks.dart
   void _beginFrame(int microseconds) {
-    assert(_debugRenderedViews == null);
-    assert(_debugRenderedViewsBetweenCallbacks == null);
-    assert(() {
-      _debugRenderedViews = <FlutterView>{};
-      return true;
-    }());
-
     _invoke1<Duration>(
       onBeginFrame,
       _onBeginFrameZone,
       Duration(microseconds: microseconds),
     );
-
-    assert(_debugRenderedViews != null);
-    assert(_debugRenderedViewsBetweenCallbacks == null);
-    assert(() {
-      _debugRenderedViewsBetweenCallbacks = _debugRenderedViews;
-      _debugRenderedViews = null;
-      return true;
-    }());
   }
 
   /// A callback that is invoked for each frame after [onBeginFrame] has
@@ -388,22 +350,7 @@ class PlatformDispatcher {
 
   // Called from the engine, via hooks.dart
   void _drawFrame() {
-    assert(_debugRenderedViews == null);
-    assert(_debugRenderedViewsBetweenCallbacks != null);
-    assert(() {
-      _debugRenderedViews = _debugRenderedViewsBetweenCallbacks;
-      _debugRenderedViewsBetweenCallbacks = null;
-      return true;
-    }());
-
     _invoke(onDrawFrame, _onDrawFrameZone);
-
-    assert(_debugRenderedViews != null);
-    assert(_debugRenderedViewsBetweenCallbacks == null);
-    assert(() {
-      _debugRenderedViews = null;
-      return true;
-    }());
   }
 
   /// A callback that is invoked when pointer data is available.

lib/ui/window.dart

@@ -372,22 +372,11 @@ class FlutterView {
   /// * [RendererBinding], the Flutter framework class which manages layout and
   ///   painting.
   void render(Scene scene, {Size? size}) {
-    // Duplicated calls or calls outside of onBeginFrame/onDrawFrame (indicated
-    // by _debugRenderedViews being null) are ignored. See _debugRenderedViews.
-    // TODO(dkwingsmt): We should change this skip into an assertion.
-    // https://github.com/flutter/flutter/issues/137073
-    bool validRender = true;
-    assert(() {
-      validRender = platformDispatcher._debugRenderedViews?.add(this) ?? false;
-      return true;
-    }());
-    if (validRender) {
-      _render(scene as _NativeScene, size?.width ?? physicalSize.width, size?.height ?? physicalSize.height);
-    }
+    _render(viewId, scene as _NativeScene, size?.width ?? physicalSize.width, size?.height ?? physicalSize.height);
   }
 
-  @Native<Void Function(Pointer<Void>, Double, Double)>(symbol: 'PlatformConfigurationNativeApi::Render')
-  external static void _render(_NativeScene scene, double width, double height);
+  @Native<Void Function(Int64, Pointer<Void>, Double, Double)>(symbol: 'PlatformConfigurationNativeApi::Render')
+  external static void _render(int viewId, _NativeScene scene, double width, double height);
 
   /// Change the retained semantics data about this [FlutterView].
   ///

lib/ui/window/platform_configuration.cc

@@ -449,9 +449,13 @@ void PlatformConfiguration::CompletePlatformMessageResponse(
   response->Complete(std::make_unique<fml::DataMapping>(std::move(data)));
 }
 
-void PlatformConfigurationNativeApi::Render(Scene* scene,
+void PlatformConfigurationNativeApi::Render(int64_t view_id,
+                                            Scene* scene,
                                             double width,
                                             double height) {
+  // TODO(dkwingsmt): Currently only supports a single window.
+  // See https://github.com/flutter/flutter/issues/135530, item 2.
+  FML_DCHECK(view_id == kFlutterImplicitViewId);
   UIDartState::ThrowIfUIOperationsProhibited();
   UIDartState::Current()->platform_configuration()->client()->Render(
       scene, width, height);

lib/ui/window/platform_configuration.h

@@ -557,7 +557,10 @@ class PlatformConfigurationNativeApi {
 
   static void ScheduleFrame();
 
-  static void Render(Scene* scene, double width, double height);
+  static void Render(int64_t view_id,
+                     Scene* scene,
+                     double width,
+                     double height);
 
   static void UpdateSemantics(SemanticsUpdate* update);