[engine] remove raster stats feature. (flutter#54187)

This debugging tool does not give accurate measurements and we've decided to remove it.

See also: flutter/flutter#131941

ci/licenses_golden/licenses_flutter

@@ -41667,8 +41667,6 @@ ORIGIN: ../../../flutter/flow/flow_test_utils.cc + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/flow/flow_test_utils.h + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/flow/frame_timings.cc + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/flow/frame_timings.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/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
@@ -44551,8 +44549,6 @@ FILE: ../../../flutter/flow/flow_test_utils.cc
 FILE: ../../../flutter/flow/flow_test_utils.h
 FILE: ../../../flutter/flow/frame_timings.cc
 FILE: ../../../flutter/flow/frame_timings.h
-FILE: ../../../flutter/flow/layer_snapshot_store.cc
-FILE: ../../../flutter/flow/layer_snapshot_store.h
 FILE: ../../../flutter/flow/layers/backdrop_filter_layer.cc
 FILE: ../../../flutter/flow/layers/backdrop_filter_layer.h
 FILE: ../../../flutter/flow/layers/cacheable_layer.cc

flow/BUILD.gn

@@ -21,8 +21,6 @@ source_set("flow") {
     "embedded_views.h",
     "frame_timings.cc",
     "frame_timings.h",
-    "layer_snapshot_store.cc",
-    "layer_snapshot_store.h",
     "layers/backdrop_filter_layer.cc",
     "layers/backdrop_filter_layer.h",
     "layers/cacheable_layer.cc",

flow/compositor_context.h

@@ -12,7 +12,6 @@
 #include "flutter/common/macros.h"
 #include "flutter/flow/diff_context.h"
 #include "flutter/flow/embedded_views.h"
-#include "flutter/flow/layer_snapshot_store.h"
 #include "flutter/flow/raster_cache.h"
 #include "flutter/flow/stopwatch.h"
 #include "flutter/fml/macros.h"
@@ -195,14 +194,11 @@ class CompositorContext {
 
   Stopwatch& ui_time() { return ui_time_; }
 
-  LayerSnapshotStore& snapshot_store() { return layer_snapshot_store_; }
-
  private:
   NOT_SLIMPELLER(RasterCache raster_cache_);
   std::shared_ptr<TextureRegistry> texture_registry_;
   Stopwatch raster_time_;
   Stopwatch ui_time_;
-  LayerSnapshotStore layer_snapshot_store_;
 
   /// Only used by default constructor of `CompositorContext`.
   FixedRefreshRateUpdater fixed_refresh_rate_updater_;

flow/layers/display_list_layer.cc

@@ -7,7 +7,6 @@
 #include <utility>
 
 #include "flutter/display_list/dl_builder.h"
-#include "flutter/flow/layer_snapshot_store.h"
 #include "flutter/flow/layers/cacheable_layer.h"
 #include "flutter/flow/layers/offscreen_surface.h"
 #include "flutter/flow/raster_cache.h"
@@ -132,40 +131,6 @@ void DisplayListLayer::Paint(PaintContext& context) const {
 #endif  //  !SLIMPELLER
 
   SkScalar opacity = context.state_stack.outstanding_opacity();
-
-#if !SLIMPELLER
-  // Leaf layer tracing was never supported in the Impeller backend.
-  if (context.enable_leaf_layer_tracing) {
-    const auto canvas_size = context.canvas->GetBaseLayerSize();
-    auto offscreen_surface =
-        std::make_unique<OffscreenSurface>(context.gr_context, canvas_size);
-
-    const auto& ctm = context.canvas->GetTransform();
-
-    const auto start_time = fml::TimePoint::Now();
-    {
-      // render display list to offscreen surface.
-      auto* canvas = offscreen_surface->GetCanvas();
-      {
-        DlAutoCanvasRestore save(canvas, true);
-        canvas->Clear(DlColor::kTransparent());
-        canvas->SetTransform(ctm);
-        canvas->DrawDisplayList(display_list_, opacity);
-      }
-      canvas->Flush();
-    }
-    const fml::TimeDelta offscreen_render_time =
-        fml::TimePoint::Now() - start_time;
-
-    const SkRect device_bounds =
-        RasterCacheUtil::GetDeviceBounds(paint_bounds(), ctm);
-    sk_sp<SkData> raster_data = offscreen_surface->GetRasterData(true);
-    LayerSnapshotData snapshot_data(unique_id(), offscreen_render_time,
-                                    raster_data, device_bounds);
-    context.layer_snapshot_store->Add(snapshot_data);
-  }
-#endif  //  !SLIMPELLER
-
   context.canvas->DrawDisplayList(display_list_, opacity);
 }
 

flow/layers/display_list_layer_unittests.cc

@@ -439,41 +439,6 @@ TEST_F(DisplayListLayerDiffTest, DisplayListCompare) {
   EXPECT_EQ(damage.frame_damage, SkIRect::MakeLTRB(20, 20, 70, 70));
 }
 
-TEST_F(DisplayListLayerTest, LayerTreeSnapshotsWhenEnabled) {
-  const SkPoint layer_offset = SkPoint::Make(1.5f, -0.5f);
-  const SkRect picture_bounds = SkRect::MakeLTRB(5.0f, 6.0f, 20.5f, 21.5f);
-  DisplayListBuilder builder;
-  builder.DrawRect(picture_bounds, DlPaint());
-  auto display_list = builder.Build();
-  auto layer = std::make_shared<DisplayListLayer>(layer_offset, display_list,
-                                                  false, false);
-
-  layer->Preroll(preroll_context());
-
-  enable_leaf_layer_tracing();
-  layer->Paint(paint_context());
-  disable_leaf_layer_tracing();
-
-  auto& snapshot_store = layer_snapshot_store();
-  EXPECT_EQ(1u, snapshot_store.Size());
-}
-
-TEST_F(DisplayListLayerTest, NoLayerTreeSnapshotsWhenDisabledByDefault) {
-  const SkPoint layer_offset = SkPoint::Make(1.5f, -0.5f);
-  const SkRect picture_bounds = SkRect::MakeLTRB(5.0f, 6.0f, 20.5f, 21.5f);
-  DisplayListBuilder builder;
-  builder.DrawRect(picture_bounds, DlPaint());
-  auto display_list = builder.Build();
-  auto layer = std::make_shared<DisplayListLayer>(layer_offset, display_list,
-                                                  false, false);
-
-  layer->Preroll(preroll_context());
-  layer->Paint(paint_context());
-
-  auto& snapshot_store = layer_snapshot_store();
-  EXPECT_EQ(0u, snapshot_store.Size());
-}
-
 TEST_F(DisplayListLayerTest, DisplayListAccessCountDependsOnVisibility) {
   const SkPoint layer_offset = SkPoint::Make(1.5f, -0.5f);
   const SkRect picture_bounds = SkRect::MakeLTRB(5.0f, 6.0f, 20.5f, 21.5f);

flow/layers/layer.h

@@ -15,7 +15,6 @@
 #include "flutter/display_list/dl_canvas.h"
 #include "flutter/flow/diff_context.h"
 #include "flutter/flow/embedded_views.h"
-#include "flutter/flow/layer_snapshot_store.h"
 #include "flutter/flow/layers/layer_state_stack.h"
 #include "flutter/flow/raster_cache.h"
 #include "flutter/flow/stopwatch.h"
@@ -114,10 +113,6 @@ struct PaintContext {
   std::shared_ptr<TextureRegistry> texture_registry;
   NOT_SLIMPELLER(const RasterCache* raster_cache);
 
-  // Snapshot store to collect leaf layer snapshots. The store is non-null
-  // only when leaf layer tracing is enabled.
-  LayerSnapshotStore* layer_snapshot_store = nullptr;
-  bool enable_leaf_layer_tracing = false;
   bool impeller_enabled = false;
   impeller::AiksContext* aiks_context;
 };

flow/layers/layer_tree.cc

@@ -7,7 +7,6 @@
 #include "flutter/display_list/skia/dl_sk_canvas.h"
 #include "flutter/flow/embedded_views.h"
 #include "flutter/flow/frame_timings.h"
-#include "flutter/flow/layer_snapshot_store.h"
 #include "flutter/flow/layers/layer.h"
 #include "flutter/flow/paint_utils.h"
 #include "flutter/flow/raster_cache.h"
@@ -108,13 +107,6 @@ void LayerTree::Paint(CompositorContext::ScopedFrame& frame,
   DlCanvas* canvas = frame.canvas();
   state_stack.set_delegate(canvas);
 
-  // clear the previous snapshots.
-  LayerSnapshotStore* snapshot_store = nullptr;
-  if (enable_leaf_layer_tracing_) {
-    frame.context().snapshot_store().Clear();
-    snapshot_store = &frame.context().snapshot_store();
-  }
-
   SkColorSpace* color_space = GetColorSpace(frame.canvas());
 
 #if !SLIMPELLER
@@ -135,8 +127,6 @@ void LayerTree::Paint(CompositorContext::ScopedFrame& frame,
 #if !SLIMPELLER
       .raster_cache                  = cache,
 #endif  //  !SLIMPELLER
-      .layer_snapshot_store          = snapshot_store,
-      .enable_leaf_layer_tracing     = enable_leaf_layer_tracing_,
       .impeller_enabled              = !!frame.aiks_context(),
       .aiks_context                  = frame.aiks_context(),
       // clang-format on
@@ -198,8 +188,6 @@ sk_sp<DisplayList> LayerTree::Flatten(
 #if !SLIMPELLER
       .raster_cache                  = nullptr,
 #endif  //  !SLIMPELLER
-      .layer_snapshot_store          = nullptr,
-      .enable_leaf_layer_tracing     = false,
       // clang-format on
   };
 

flow/layers/layer_tree.h

@@ -56,24 +56,9 @@ class LayerTree {
   const PaintRegionMap& paint_region_map() const { return paint_region_map_; }
   PaintRegionMap& paint_region_map() { return paint_region_map_; }
 
-  /// When `Paint` is called, if leaf layer tracing is enabled, additional
-  /// metadata around rasterization of leaf layers is collected.
-  ///
-  /// This is not supported in the Impeller backend.
-  ///
-  /// See: `LayerSnapshotStore`
-  void enable_leaf_layer_tracing(bool enable) {
-    enable_leaf_layer_tracing_ = enable;
-  }
-
-  bool is_leaf_layer_tracing_enabled() const {
-    return enable_leaf_layer_tracing_;
-  }
-
  private:
   std::shared_ptr<Layer> root_layer_;
   SkISize frame_size_ = SkISize::MakeEmpty();  // Physical pixels.
-  bool enable_leaf_layer_tracing_ = false;
 
   PaintRegionMap paint_region_map_;
 

flow/layers/layer_tree_unittests.cc

@@ -250,9 +250,6 @@ TEST_F(LayerTreeTest, PaintContextInitialization) {
     EXPECT_EQ(&context.ui_time, &mock_ui_time);
     EXPECT_EQ(context.texture_registry.get(), mock_registry.get());
     EXPECT_EQ(context.raster_cache, nullptr);
-
-    EXPECT_EQ(context.enable_leaf_layer_tracing, false);
-    EXPECT_EQ(context.layer_snapshot_store, nullptr);
   };
 
   // These 4 initializers are required because they are handled by reference

flow/testing/layer_test.h

@@ -6,7 +6,6 @@
 #define FLUTTER_FLOW_TESTING_LAYER_TEST_H_
 
 #include "display_list/dl_color.h"
-#include "flutter/flow/layer_snapshot_store.h"
 #include "flutter/flow/layers/layer.h"
 
 #include <optional>
@@ -153,7 +152,6 @@ class LayerTestBase : public CanvasTestBase<BaseT> {
   PaintContext& display_list_paint_context() {
     return display_list_paint_context_;
   }
-  LayerSnapshotStore& layer_snapshot_store() { return snapshot_store_; }
 
   sk_sp<DisplayList> display_list() {
     if (display_list_ == nullptr) {
@@ -170,16 +168,6 @@ class LayerTestBase : public CanvasTestBase<BaseT> {
     FML_DCHECK(display_list_state_stack_.is_empty());
   }
 
-  void enable_leaf_layer_tracing() {
-    paint_context_.enable_leaf_layer_tracing = true;
-    paint_context_.layer_snapshot_store = &snapshot_store_;
-  }
-
-  void disable_leaf_layer_tracing() {
-    paint_context_.enable_leaf_layer_tracing = false;
-    paint_context_.layer_snapshot_store = nullptr;
-  }
-
  private:
   void set_raster_cache_(std::unique_ptr<RasterCache> raster_cache) {
     raster_cache_ = std::move(raster_cache);
@@ -201,7 +189,6 @@ class LayerTestBase : public CanvasTestBase<BaseT> {
   LayerStateStack display_list_state_stack_;
   sk_sp<DisplayList> display_list_;
   PaintContext display_list_paint_context_;
-  LayerSnapshotStore snapshot_store_;
 
   std::vector<RasterCacheItem*> cacheable_items_;