[Impeller] DlCanvas implementation wrapping Aiks canvas (#44248)

Fixes flutter/flutter#130141

The primary goal of this patch is to move dispatching of `dart:ui` `Canvas` commands to the UI thread.

Before this patch, the architecture is something like:

## UI Thread
- `dart:ui` talks to `DisplayListBuilder`, a `DlCanvas` implementation.
- `DisplayListBuilder` does some clip/bounds tracking and creates a `DisplayList` object that is held by `dart:ui`'s `Picture` objects.
- `DisplayList`s are added to `DisplayListLayer`s in `flow`. 

## Raster Thread
- `flow` flattens the various operations into a single `DisplayList` via another `DisplayListBuilder`.
- A `DlOpReceiver`implementation converts that `DisplayList` into an `Aiks` `Canvas`/`Picture`.

After this patch, the architecture instead looks like:

## UI Thread

- No change for Skia.
- If Impeller, use a new `DlCanvasImplementation` that talks to `Aiks`'s `Canvas`.
- If Impeller, `dart:ui` Picture's now hold an `Aiks` `Picture`, which get shared into `AiksLayer`s in `flow`.

## Raster thread

- No change for Skia, but some light refactoring for places that assumed a `DisplayListBuilder` where they really just needed a `DlCanvas`.
- The `Aiks` `Picture`s are combined using new API on `DlCanvas` and still backed by `Aiks`.

These changes show significant improvement on raster times on Android and only very small regressions on UI times in local testing, see https://gist.github.com/dnfield/26528090194c9f5abdbac13cdcbf4f79 for old gallery transition perf numbers.

Many of the other changes in this patch are related to the following:

- Making `DlRTree` usable for Impeller.
  - It would be nice to have a version of DlRTree that speaks `impeller::Rect`.
- Creating the requisite classes to support `EmbeddedViews` so that Desktop works.

This patch does not remove the `impeller::DlDispatcher`, which now would only be used in tests.

ci/licenses_golden/excluded_files

@@ -32,6 +32,7 @@
 ../../../flutter/display_list/benchmarking/dl_complexity_unittests.cc
 ../../../flutter/display_list/display_list_unittests.cc
 ../../../flutter/display_list/dl_color_unittests.cc
+../../../flutter/display_list/dl_op_spy_unittests.cc
 ../../../flutter/display_list/dl_paint_unittests.cc
 ../../../flutter/display_list/dl_vertices_unittests.cc
 ../../../flutter/display_list/effects/dl_color_filter_unittests.cc
@@ -215,7 +216,6 @@
 ../../../flutter/runtime/type_conversions_unittests.cc
 ../../../flutter/shell/common/animator_unittests.cc
 ../../../flutter/shell/common/context_options_unittests.cc
-../../../flutter/shell/common/dl_op_spy_unittests.cc
 ../../../flutter/shell/common/engine_unittests.cc
 ../../../flutter/shell/common/fixtures
 ../../../flutter/shell/common/input_events_unittests.cc

ci/licenses_golden/licenses_flutter

@@ -731,6 +731,8 @@ ORIGIN: ../../../flutter/display_list/dl_op_receiver.cc + ../../../flutter/LICEN
 ORIGIN: ../../../flutter/display_list/dl_op_receiver.h + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/display_list/dl_op_records.cc + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/display_list/dl_op_records.h + ../../../flutter/LICENSE
+ORIGIN: ../../../flutter/display_list/dl_op_spy.cc + ../../../flutter/LICENSE
+ORIGIN: ../../../flutter/display_list/dl_op_spy.h + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/display_list/dl_paint.cc + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/display_list/dl_paint.h + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/display_list/dl_sampling_options.h + ../../../flutter/LICENSE
@@ -787,6 +789,8 @@ ORIGIN: ../../../flutter/flow/instrumentation.cc + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/flow/instrumentation.h + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/flow/layer_snapshot_store.cc + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/flow/layer_snapshot_store.h + ../../../flutter/LICENSE
+ORIGIN: ../../../flutter/flow/layers/aiks_layer.cc + ../../../flutter/LICENSE
+ORIGIN: ../../../flutter/flow/layers/aiks_layer.h + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/flow/layers/backdrop_filter_layer.cc + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/flow/layers/backdrop_filter_layer.h + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/flow/layers/cacheable_layer.cc + ../../../flutter/LICENSE
@@ -1153,6 +1157,8 @@ ORIGIN: ../../../flutter/impeller/core/texture_descriptor.cc + ../../../flutter/
 ORIGIN: ../../../flutter/impeller/core/texture_descriptor.h + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/impeller/core/vertex_buffer.cc + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/impeller/core/vertex_buffer.h + ../../../flutter/LICENSE
+ORIGIN: ../../../flutter/impeller/display_list/dl_aiks_canvas.cc + ../../../flutter/LICENSE
+ORIGIN: ../../../flutter/impeller/display_list/dl_aiks_canvas.h + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/impeller/display_list/dl_dispatcher.cc + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/impeller/display_list/dl_dispatcher.h + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/impeller/display_list/dl_image_impeller.cc + ../../../flutter/LICENSE
@@ -2210,8 +2216,6 @@ ORIGIN: ../../../flutter/shell/common/display.cc + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/shell/common/display.h + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/shell/common/display_manager.cc + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/shell/common/display_manager.h + ../../../flutter/LICENSE
-ORIGIN: ../../../flutter/shell/common/dl_op_spy.cc + ../../../flutter/LICENSE
-ORIGIN: ../../../flutter/shell/common/dl_op_spy.h + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/shell/common/engine.cc + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/shell/common/engine.h + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/shell/common/pipeline.cc + ../../../flutter/LICENSE
@@ -3441,6 +3445,8 @@ FILE: ../../../flutter/display_list/dl_op_receiver.cc
 FILE: ../../../flutter/display_list/dl_op_receiver.h
 FILE: ../../../flutter/display_list/dl_op_records.cc
 FILE: ../../../flutter/display_list/dl_op_records.h
+FILE: ../../../flutter/display_list/dl_op_spy.cc
+FILE: ../../../flutter/display_list/dl_op_spy.h
 FILE: ../../../flutter/display_list/dl_paint.cc
 FILE: ../../../flutter/display_list/dl_paint.h
 FILE: ../../../flutter/display_list/dl_sampling_options.h
@@ -3497,6 +3503,8 @@ FILE: ../../../flutter/flow/instrumentation.cc
 FILE: ../../../flutter/flow/instrumentation.h
 FILE: ../../../flutter/flow/layer_snapshot_store.cc
 FILE: ../../../flutter/flow/layer_snapshot_store.h
+FILE: ../../../flutter/flow/layers/aiks_layer.cc
+FILE: ../../../flutter/flow/layers/aiks_layer.h
 FILE: ../../../flutter/flow/layers/backdrop_filter_layer.cc
 FILE: ../../../flutter/flow/layers/backdrop_filter_layer.h
 FILE: ../../../flutter/flow/layers/cacheable_layer.cc
@@ -3863,6 +3871,8 @@ FILE: ../../../flutter/impeller/core/texture_descriptor.cc
 FILE: ../../../flutter/impeller/core/texture_descriptor.h
 FILE: ../../../flutter/impeller/core/vertex_buffer.cc
 FILE: ../../../flutter/impeller/core/vertex_buffer.h
+FILE: ../../../flutter/impeller/display_list/dl_aiks_canvas.cc
+FILE: ../../../flutter/impeller/display_list/dl_aiks_canvas.h
 FILE: ../../../flutter/impeller/display_list/dl_dispatcher.cc
 FILE: ../../../flutter/impeller/display_list/dl_dispatcher.h
 FILE: ../../../flutter/impeller/display_list/dl_image_impeller.cc
@@ -4925,8 +4935,6 @@ FILE: ../../../flutter/shell/common/display.cc
 FILE: ../../../flutter/shell/common/display.h
 FILE: ../../../flutter/shell/common/display_manager.cc
 FILE: ../../../flutter/shell/common/display_manager.h
-FILE: ../../../flutter/shell/common/dl_op_spy.cc
-FILE: ../../../flutter/shell/common/dl_op_spy.h
 FILE: ../../../flutter/shell/common/engine.cc
 FILE: ../../../flutter/shell/common/engine.h
 FILE: ../../../flutter/shell/common/pipeline.cc

display_list/BUILD.gn

@@ -39,6 +39,8 @@ source_set("display_list") {
     "dl_op_receiver.h",
     "dl_op_records.cc",
     "dl_op_records.h",
+    "dl_op_spy.cc",
+    "dl_op_spy.h",
     "dl_paint.cc",
     "dl_paint.h",
     "dl_sampling_options.h",
@@ -107,6 +109,7 @@ if (enable_unittests) {
       "benchmarking/dl_complexity_unittests.cc",
       "display_list_unittests.cc",
       "dl_color_unittests.cc",
+      "dl_op_spy_unittests.cc",
       "dl_paint_unittests.cc",
       "dl_vertices_unittests.cc",
       "effects/dl_color_filter_unittests.cc",

display_list/display_list.cc

@@ -34,7 +34,7 @@ DisplayList::DisplayList(DisplayListStorage&& storage,
                          bool can_apply_group_opacity,
                          bool is_ui_thread_safe,
                          bool modifies_transparent_black,
-                         sk_sp<const DlRTree> rtree)
+                         std::shared_ptr<const DlRTree> rtree)
     : storage_(std::move(storage)),
       byte_count_(byte_count),
       op_count_(op_count),

display_list/display_list.h

@@ -254,7 +254,7 @@ class DisplayList : public SkRefCnt {
   const SkRect& bounds() const { return bounds_; }
 
   bool has_rtree() const { return rtree_ != nullptr; }
-  sk_sp<const DlRTree> rtree() const { return rtree_; }
+  std::shared_ptr<const DlRTree> rtree() const { return rtree_; }
 
   bool Equals(const DisplayList* other) const;
   bool Equals(const DisplayList& other) const { return Equals(&other); }
@@ -288,7 +288,7 @@ class DisplayList : public SkRefCnt {
               bool can_apply_group_opacity,
               bool is_ui_thread_safe,
               bool modifies_transparent_black,
-              sk_sp<const DlRTree> rtree);
+              std::shared_ptr<const DlRTree> rtree);
 
   static uint32_t next_unique_id();
 
@@ -308,7 +308,7 @@ class DisplayList : public SkRefCnt {
   const bool is_ui_thread_safe_;
   const bool modifies_transparent_black_;
 
-  const sk_sp<const DlRTree> rtree_;
+  const std::shared_ptr<const DlRTree> rtree_;
 
   void Dispatch(DlOpReceiver& ctx,
                 uint8_t* ptr,

display_list/display_list_unittests.cc

@@ -2130,7 +2130,7 @@ TEST_F(DisplayListTest, FlatDrawPointsProducesBounds) {
   }
 }
 
-static void test_rtree(const sk_sp<const DlRTree>& rtree,
+static void test_rtree(const std::shared_ptr<const DlRTree>& rtree,
                        const SkRect& query,
                        std::vector<SkRect> expected_rects,
                        const std::vector<int>& expected_indices) {

display_list/dl_builder.cc

@@ -1208,6 +1208,13 @@ void DisplayListBuilder::DrawAtlas(const sk_sp<DlImage>& atlas,
   }
 }
 
+void DisplayListBuilder::DrawImpellerPicture(
+    const std::shared_ptr<const impeller::Picture>& picture,
+    SkScalar opacity) {
+  FML_LOG(ERROR) << "Cannot draw Impeller Picture in to a a display list.";
+  FML_DCHECK(false);
+}
+
 void DisplayListBuilder::DrawDisplayList(const sk_sp<DisplayList> display_list,
                                          SkScalar opacity) {
   if (!SkScalarIsFinite(opacity) || opacity <= SK_ScalarNearlyZero ||

display_list/dl_builder.h

@@ -216,6 +216,12 @@ class DisplayListBuilder final : public virtual DlCanvas,
                  DlImageSampling sampling,
                  const SkRect* cullRect,
                  const DlPaint* paint = nullptr) override;
+
+  // |DlCanvas|
+  void DrawImpellerPicture(
+      const std::shared_ptr<const impeller::Picture>& picture,
+      SkScalar opacity = SK_Scalar1) override;
+
   // |DlCanvas|
   void DrawDisplayList(const sk_sp<DisplayList> display_list,
                        SkScalar opacity = SK_Scalar1) override;
@@ -701,7 +707,7 @@ class DisplayListBuilder final : public virtual DlCanvas,
     return accumulator_->bounds();
   }
 
-  sk_sp<DlRTree> rtree() {
+  std::shared_ptr<DlRTree> rtree() {
     FML_DCHECK(layer_stack_.size() == 1);
     if (is_unbounded()) {
       FML_LOG(INFO) << "returning partial rtree for unbounded DisplayList";

display_list/dl_canvas.h

@@ -18,6 +18,10 @@
 #include "third_party/skia/include/core/SkRect.h"
 #include "third_party/skia/include/core/SkTextBlob.h"
 
+namespace impeller {
+struct Picture;
+}  // namespace impeller
+
 namespace flutter {
 
 // The primary class used to express rendering operations in the
@@ -59,7 +63,12 @@ class DlCanvas {
                          const DlImageFilter* backdrop = nullptr) = 0;
   virtual void Restore() = 0;
   virtual int GetSaveCount() const = 0;
-  virtual void RestoreToCount(int restore_count) = 0;
+  virtual void RestoreToCount(int restore_count) {
+    FML_DCHECK(restore_count <= GetSaveCount());
+    while (restore_count < GetSaveCount() && GetSaveCount() > 1) {
+      Restore();
+    }
+  }
 
   virtual void Translate(SkScalar tx, SkScalar ty) = 0;
   virtual void Scale(SkScalar sx, SkScalar sy) = 0;
@@ -199,6 +208,9 @@ class DlCanvas {
                          const DlPaint* paint = nullptr) = 0;
   virtual void DrawDisplayList(const sk_sp<DisplayList> display_list,
                                SkScalar opacity = SK_Scalar1) = 0;
+  virtual void DrawImpellerPicture(
+      const std::shared_ptr<const impeller::Picture>& picture,
+      SkScalar opacity = SK_Scalar1) = 0;
   virtual void DrawTextBlob(const sk_sp<SkTextBlob>& blob,
                             SkScalar x,
                             SkScalar y,

shell/common/dl_op_spy.cc → display_list/dl_op_spy.cc

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "flutter/shell/common/dl_op_spy.h"
+#include "flutter/display_list/dl_op_spy.h"
 
 namespace flutter {
 

shell/common/dl_op_spy.h → display_list/dl_op_spy.h

@@ -2,8 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef FLUTTER_DISPLAY_LIST_DL_OP_SPY_H_
-#define FLUTTER_DISPLAY_LIST_DL_OP_SPY_H_
+#pragma once
 
 #include "flutter/display_list/dl_op_receiver.h"
 #include "flutter/display_list/utils/dl_receiver_utils.h"
@@ -105,5 +104,3 @@ class DlOpSpy final : public virtual DlOpReceiver,
 };
 
 }  // namespace flutter
-
-#endif  // FLUTTER_DISPLAY_LIST_DL_OP_SPY_H_

shell/common/dl_op_spy_unittests.cc → display_list/dl_op_spy_unittests.cc

@@ -4,7 +4,7 @@
 
 #include "flutter/display_list/display_list.h"
 #include "flutter/display_list/dl_builder.h"
-#include "flutter/shell/common/dl_op_spy.h"
+#include "flutter/display_list/dl_op_spy.h"
 #include "flutter/testing/testing.h"
 #include "third_party/skia/include/core/SkBitmap.h"
 #include "third_party/skia/include/core/SkRSXform.h"

display_list/geometry/dl_rtree.h

@@ -25,7 +25,7 @@ namespace flutter {
 /// - Query for a set of non-overlapping rectangles that are joined
 ///   from the original rectangles that intersect a query rect
 ///   @see |searchAndConsolidateRects|
-class DlRTree : public SkRefCnt {
+class DlRTree {
  private:
   static constexpr int kMaxChildren = 11;
 

display_list/skia/dl_sk_canvas.cc

@@ -335,6 +335,13 @@ void DlSkCanvasAdapter::DrawAtlas(const sk_sp<DlImage>& atlas,
                        ToSk(sampling), cullRect, sk_paint());
 }
 
+void DlSkCanvasAdapter::DrawImpellerPicture(
+    const std::shared_ptr<const impeller::Picture>& picture,
+    SkScalar opacity) {
+  FML_LOG(ERROR) << "Cannot draw Impeller Picture in to a Skia canvas.";
+  FML_DCHECK(false);
+}
+
 void DlSkCanvasAdapter::DrawDisplayList(const sk_sp<DisplayList> display_list,
                                         SkScalar opacity) {
   const int restore_count = delegate_->getSaveCount();

display_list/skia/dl_sk_canvas.h

@@ -136,6 +136,9 @@ class DlSkCanvasAdapter final : public virtual DlCanvas {
                  DlImageSampling sampling,
                  const SkRect* cullRect,
                  const DlPaint* paint = nullptr) override;
+  void DrawImpellerPicture(
+      const std::shared_ptr<const impeller::Picture>& picture,
+      SkScalar opacity = SK_Scalar1) override;
   void DrawDisplayList(const sk_sp<DisplayList> display_list,
                        SkScalar opacity = SK_Scalar1) override;
   void DrawTextBlob(const sk_sp<SkTextBlob>& blob,

display_list/utils/dl_bounds_accumulator.cc

@@ -125,10 +125,11 @@ SkRect RTreeBoundsAccumulator::bounds() const {
   return accumulator.bounds();
 }
 
-sk_sp<DlRTree> RTreeBoundsAccumulator::rtree() const {
+std::shared_ptr<DlRTree> RTreeBoundsAccumulator::rtree() const {
   FML_DCHECK(saved_offsets_.empty());
-  return sk_make_sp<DlRTree>(rects_.data(), rects_.size(), rect_indices_.data(),
-                             [](int id) { return id >= 0; });
+  return std::make_shared<DlRTree>(rects_.data(), rects_.size(),
+                                   rect_indices_.data(),
+                                   [](int id) { return id >= 0; });
 }
 
 }  // namespace flutter

display_list/utils/dl_bounds_accumulator.h

@@ -84,7 +84,7 @@ class BoundsAccumulator {
 
   virtual SkRect bounds() const = 0;
 
-  virtual sk_sp<DlRTree> rtree() const = 0;
+  virtual std::shared_ptr<DlRTree> rtree() const = 0;
 
   virtual BoundsAccumulatorType type() const = 0;
 };
@@ -112,7 +112,7 @@ class RectBoundsAccumulator final : public virtual BoundsAccumulator {
     return BoundsAccumulatorType::kRect;
   }
 
-  sk_sp<DlRTree> rtree() const override { return nullptr; }
+  std::shared_ptr<DlRTree> rtree() const override { return nullptr; }
 
  private:
   class AccumulationRect {
@@ -151,7 +151,7 @@ class RTreeBoundsAccumulator final : public virtual BoundsAccumulator {
 
   SkRect bounds() const override;
 
-  sk_sp<DlRTree> rtree() const override;
+  std::shared_ptr<DlRTree> rtree() const override;
 
   BoundsAccumulatorType type() const override {
     return BoundsAccumulatorType::kRTree;

flow/BUILD.gn

@@ -22,6 +22,8 @@ source_set("flow") {
     "instrumentation.h",
     "layer_snapshot_store.cc",
     "layer_snapshot_store.h",
+    "layers/aiks_layer.cc",
+    "layers/aiks_layer.h",
     "layers/backdrop_filter_layer.cc",
     "layers/backdrop_filter_layer.h",
     "layers/cacheable_layer.cc",