Revert "Fix composition when multiple platform views and layers are combined (#25900)" (#26142)

This appears to be reliably crashing the devicelab
linux_android_view_scroll_perf__timeline_summary test.

Example crashes:
* https://ci.chromium.org/ui/p/flutter/builders/prod/Linux%20android_view_scroll_perf__timeline_summary/1369/overview
* https://ci.chromium.org/ui/p/flutter/builders/prod/Linux%20android_view_scroll_perf__timeline_summary/1370/overview

This reverts commit cf18983.

Author: cbracken

shell/platform/android/external_view_embedder/external_view_embedder.cc

@@ -84,7 +84,7 @@ void AndroidExternalViewEmbedder::SubmitFrame(
     return;
   }
 
-  std::unordered_map<int64_t, SkRect> overlay_layers;
+  std::unordered_map<int64_t, std::list<SkRect>> overlay_layers;
   std::unordered_map<int64_t, sk_sp<SkPicture>> pictures;
   SkCanvas* background_canvas = frame->SkiaCanvas();
   auto current_frame_view_count = composition_order_.size();
@@ -101,9 +101,9 @@ void AndroidExternalViewEmbedder::SubmitFrame(
     FML_CHECK(picture);
     pictures.insert({view_id, picture});
 
-    sk_sp<RTree> rtree = view_rtrees_.at(view_id);
-    SkRect joined_rect = SkRect::MakeEmpty();
+    overlay_layers.insert({view_id, {}});
 
+    sk_sp<RTree> rtree = view_rtrees_.at(view_id);
     // Determinate if Flutter UI intersects with any of the previous
     // platform views stacked by z position.
     //
@@ -116,31 +116,33 @@ void AndroidExternalViewEmbedder::SubmitFrame(
       // Each rect corresponds to a native view that renders Flutter UI.
       std::list<SkRect> intersection_rects =
           rtree->searchNonOverlappingDrawnRects(current_view_rect);
+      auto allocation_size = intersection_rects.size();
 
       // Limit the number of native views, so it doesn't grow forever.
       //
       // In this case, the rects are merged into a single one that is the union
       // of all the rects.
-      for (const SkRect& rect : intersection_rects) {
-        joined_rect.join(rect);
+      if (allocation_size > kMaxLayerAllocations) {
+        SkRect joined_rect;
+        for (const SkRect& rect : intersection_rects) {
+          joined_rect.join(rect);
+        }
+        intersection_rects.clear();
+        intersection_rects.push_back(joined_rect);
+      }
+      for (SkRect& intersection_rect : intersection_rects) {
+        // Subpixels in the platform may not align with the canvas subpixels.
+        //
+        // To workaround it, round the floating point bounds and make the rect
+        // slightly larger. For example, {0.3, 0.5, 3.1, 4.7} becomes {0, 0, 4,
+        // 5}.
+        intersection_rect.set(intersection_rect.roundOut());
+        overlay_layers.at(view_id).push_back(intersection_rect);
+        // Clip the background canvas, so it doesn't contain any of the pixels
+        // drawn on the overlay layer.
+        background_canvas->clipRect(intersection_rect, SkClipOp::kDifference);
       }
     }
-
-    if (joined_rect.isEmpty()) {
-      continue;
-    }
-
-    // Subpixels in the platform may not align with the canvas subpixels.
-    //
-    // To workaround it, round the floating point bounds and make the rect
-    // slightly larger.
-    //
-    // For example, {0.3, 0.5, 3.1, 4.7} becomes {0, 0, 4, 5}.
-    joined_rect.set(joined_rect.roundOut());
-    overlay_layers.insert({view_id, joined_rect});
-    // Clip the background canvas, so it doesn't contain any of the pixels
-    // drawn on the overlay layer.
-    background_canvas->clipRect(joined_rect, SkClipOp::kDifference);
     background_canvas->drawPicture(pictures.at(view_id));
   }
   // Submit the background canvas frame before switching the GL context to
@@ -168,15 +170,16 @@ void AndroidExternalViewEmbedder::SubmitFrame(
         params.sizePoints().height() * device_pixel_ratio_,
         params.mutatorsStack()  //
     );
-    const SkRect& overlay_rect = overlay_layers.at(view_id);
-    std::unique_ptr<SurfaceFrame> frame =
-        CreateSurfaceIfNeeded(context,               //
-                              view_id,               //
-                              pictures.at(view_id),  //
-                              overlay_rect           //
-        );
-    if (should_submit_current_frame) {
-      frame->Submit();
+    for (const SkRect& overlay_rect : overlay_layers.at(view_id)) {
+      std::unique_ptr<SurfaceFrame> frame =
+          CreateSurfaceIfNeeded(context,               //
+                                view_id,               //
+                                pictures.at(view_id),  //
+                                overlay_rect           //
+          );
+      if (should_submit_current_frame) {
+        frame->Submit();
+      }
     }
   }
 }

shell/platform/android/external_view_embedder/external_view_embedder.h

@@ -80,6 +80,8 @@ class AndroidExternalViewEmbedder final : public ExternalViewEmbedder {
   SkRect GetViewRect(int view_id) const;
 
  private:
+  static const int kMaxLayerAllocations = 2;
+
   // The number of frames the rasterizer task runner will continue
   // to run on the platform thread after no platform view is rendered.
   //

shell/platform/android/external_view_embedder/external_view_embedder_unittests.cc

@@ -477,108 +477,6 @@ TEST(AndroidExternalViewEmbedder, SubmitFrame) {
   }
 }
 
-TEST(AndroidExternalViewEmbedder, SubmitFrame__overlayComposition) {
-  auto jni_mock = std::make_shared<JNIMock>();
-  auto android_context =
-      std::make_shared<AndroidContext>(AndroidRenderingAPI::kSoftware);
-
-  auto window = fml::MakeRefCounted<AndroidNativeWindow>(nullptr);
-  auto gr_context = GrDirectContext::MakeMock(nullptr);
-  auto frame_size = SkISize::Make(1000, 1000);
-  auto surface_factory = std::make_shared<TestAndroidSurfaceFactory>(
-      [&android_context, gr_context, window, frame_size]() {
-        auto surface_frame_1 = std::make_unique<SurfaceFrame>(
-            SkSurface::MakeNull(1000, 1000), false,
-            [](const SurfaceFrame& surface_frame, SkCanvas* canvas) {
-              return true;
-            });
-
-        auto surface_mock = std::make_unique<SurfaceMock>();
-        EXPECT_CALL(*surface_mock, AcquireFrame(frame_size))
-            .Times(1 /* frames */)
-            .WillOnce(Return(ByMove(std::move(surface_frame_1))));
-
-        auto android_surface_mock =
-            std::make_unique<AndroidSurfaceMock>(android_context);
-        EXPECT_CALL(*android_surface_mock, IsValid()).WillOnce(Return(true));
-
-        EXPECT_CALL(*android_surface_mock, CreateGPUSurface(gr_context.get()))
-            .WillOnce(Return(ByMove(std::move(surface_mock))));
-
-        EXPECT_CALL(*android_surface_mock, SetNativeWindow(window));
-        return android_surface_mock;
-      });
-  auto embedder = std::make_unique<AndroidExternalViewEmbedder>(
-      *android_context, jni_mock, surface_factory);
-
-  auto raster_thread_merger =
-      GetThreadMergerFromPlatformThread(/*merged=*/true);
-
-  EXPECT_CALL(*jni_mock, FlutterViewBeginFrame());
-  embedder->BeginFrame(frame_size, nullptr, 1.5, raster_thread_merger);
-
-  {
-    // Add first Android view.
-    SkMatrix matrix;
-    MutatorsStack stack;
-    stack.PushTransform(SkMatrix::Translate(0, 0));
-
-    embedder->PrerollCompositeEmbeddedView(
-        0, std::make_unique<EmbeddedViewParams>(matrix, SkSize::Make(200, 200),
-                                                stack));
-    EXPECT_CALL(*jni_mock, FlutterViewOnDisplayPlatformView(0, 0, 0, 200, 200,
-                                                            300, 300, stack));
-  }
-
-  auto rect_paint = SkPaint();
-  rect_paint.setColor(SkColors::kCyan);
-  rect_paint.setStyle(SkPaint::Style::kFill_Style);
-
-  // This simulates Flutter UI that intersects with the first Android view.
-  embedder->CompositeEmbeddedView(0)->drawRect(
-      SkRect::MakeXYWH(25, 25, 80, 150), rect_paint);
-
-  {
-    // Add second Android view.
-    SkMatrix matrix;
-    MutatorsStack stack;
-    stack.PushTransform(SkMatrix::Translate(0, 100));
-
-    embedder->PrerollCompositeEmbeddedView(
-        1, std::make_unique<EmbeddedViewParams>(matrix, SkSize::Make(100, 100),
-                                                stack));
-    EXPECT_CALL(*jni_mock, FlutterViewOnDisplayPlatformView(1, 0, 0, 100, 100,
-                                                            150, 150, stack));
-  }
-  // This simulates Flutter UI that intersects with the first and second Android
-  // views.
-  embedder->CompositeEmbeddedView(1)->drawRect(SkRect::MakeXYWH(25, 25, 80, 50),
-                                               rect_paint);
-
-  embedder->CompositeEmbeddedView(1)->drawRect(
-      SkRect::MakeXYWH(75, 75, 30, 100), rect_paint);
-
-  EXPECT_CALL(*jni_mock, FlutterViewCreateOverlaySurface())
-      .WillRepeatedly([&]() {
-        return std::make_unique<PlatformViewAndroidJNI::OverlayMetadata>(
-            1, window);
-      });
-
-  EXPECT_CALL(*jni_mock, FlutterViewDisplayOverlaySurface(1, 25, 25, 80, 150))
-      .Times(2);
-
-  auto surface_frame = std::make_unique<SurfaceFrame>(
-      SkSurface::MakeNull(1000, 1000), false,
-      [](const SurfaceFrame& surface_frame, SkCanvas* canvas) mutable {
-        return true;
-      });
-
-  embedder->SubmitFrame(gr_context.get(), std::move(surface_frame), nullptr);
-
-  EXPECT_CALL(*jni_mock, FlutterViewEndFrame());
-  embedder->EndFrame(/*should_resubmit_frame=*/false, raster_thread_merger);
-}
-
 TEST(AndroidExternalViewEmbedder, DoesNotCallJNIPlatformThreadOnlyMethods) {
   auto jni_mock = std::make_shared<JNIMock>();