Use hint freed specifically for image disposal

lib/ui/hint_freed_delegate.h

@@ -0,0 +1,24 @@
+// 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.
+
+#ifndef FLUTTER_LIB_UI_HINT_FREED_DELEGATE_H_
+#define FLUTTER_LIB_UI_HINT_FREED_DELEGATE_H_
+
+namespace flutter {
+
+class HintFreedDelegate {
+ public:
+  //----------------------------------------------------------------------------
+  /// @brief      Notifies the engine that native bytes might be freed if a
+  ///             garbage collection ran at the next NotifyIdle period.
+  ///
+  /// @param[in]  size  The number of bytes freed. This size adds to any
+  ///                   previously supplied value, rather than replacing.
+  ///
+  virtual void HintFreed(size_t size) = 0;
+};
+
+}  // namespace flutter
+
+#endif  // FLUTTER_LIB_UI_HINT_FREED_DELEGATE_H_

lib/ui/painting/canvas.cc

@@ -198,7 +198,6 @@ void Canvas::clipPath(const CanvasPath* path, bool doAntiAlias) {
         ToDart("Canvas.clipPath called with non-genuine Path."));
     return;
   }
-  external_allocation_size_ += path->path().approximateBytesUsed();
   canvas_->clipPath(path->path(), doAntiAlias);
 }
 
@@ -310,7 +309,6 @@ void Canvas::drawPath(const CanvasPath* path,
         ToDart("Canvas.drawPath called with non-genuine Path."));
     return;
   }
-  external_allocation_size_ += path->path().approximateBytesUsed();
   canvas_->drawPath(path->path(), *paint.paint());
 }
 
@@ -391,7 +389,6 @@ void Canvas::drawPicture(Picture* picture) {
         ToDart("Canvas.drawPicture called with non-genuine Picture."));
     return;
   }
-  external_allocation_size_ += picture->GetAllocationSize();
   canvas_->drawPicture(picture->picture().get());
 }
 
@@ -424,7 +421,6 @@ void Canvas::drawVertices(const Vertices* vertices,
         ToDart("Canvas.drawVertices called with non-genuine Vertices."));
     return;
   }
-  external_allocation_size_ += vertices->GetAllocationSize();
   canvas_->drawVertices(vertices->vertices(), blend_mode, *paint.paint());
 }
 
@@ -453,7 +449,6 @@ void Canvas::drawAtlas(const Paint& paint,
   static_assert(sizeof(SkRect) == sizeof(float) * 4,
                 "SkRect doesn't use floats.");
 
-  external_allocation_size_ += atlas->GetAllocationSize();
   canvas_->drawAtlas(
       skImage.get(), reinterpret_cast<const SkRSXform*>(transforms.data()),
       reinterpret_cast<const SkRect*>(rects.data()),
@@ -477,7 +472,6 @@ void Canvas::drawShadow(const CanvasPath* path,
                      ->window()
                      ->viewport_metrics()
                      .device_pixel_ratio;
-  external_allocation_size_ += path->path().approximateBytesUsed();
   flutter::PhysicalShapeLayer::DrawShadow(canvas_, path->path(), color,
                                           elevation, transparentOccluder, dpr);
 }

lib/ui/painting/canvas.h

@@ -169,16 +169,13 @@ class Canvas : public RefCountedDartWrappable<Canvas> {
 
   static void RegisterNatives(tonic::DartLibraryNatives* natives);
 
-  size_t external_allocation_size() const { return external_allocation_size_; }
-
  private:
   explicit Canvas(SkCanvas* canvas);
 
   // The SkCanvas is supplied by a call to SkPictureRecorder::beginRecording,
   // which does not transfer ownership.  For this reason, we hold a raw
   // pointer and manually set to null in Clear.
   SkCanvas* canvas_;
-  size_t external_allocation_size_ = 0;
 };
 
 }  // namespace flutter

lib/ui/painting/image.cc

@@ -37,6 +37,10 @@ Dart_Handle CanvasImage::toByteData(int format, Dart_Handle callback) {
 }
 
 void CanvasImage::dispose() {
+  auto hint_freed_delegate = UIDartState::Current()->GetHintFreedDelegate();
+  if (hint_freed_delegate) {
+    hint_freed_delegate->HintFreed(GetAllocationSize());
+  }
   image_.reset();
   ClearDartWrapper();
 }

lib/ui/painting/picture.cc

@@ -28,20 +28,17 @@ IMPLEMENT_WRAPPERTYPEINFO(ui, Picture);
 
 DART_BIND_ALL(Picture, FOR_EACH_BINDING)
 
-fml::RefPtr<Picture> Picture::Create(Dart_Handle dart_handle,
-                                     flutter::SkiaGPUObject<SkPicture> picture,
-                                     size_t external_allocation_size) {
-  auto canvas_picture = fml::MakeRefCounted<Picture>(std::move(picture),
-                                                     external_allocation_size);
+fml::RefPtr<Picture> Picture::Create(
+    Dart_Handle dart_handle,
+    flutter::SkiaGPUObject<SkPicture> picture) {
+  auto canvas_picture = fml::MakeRefCounted<Picture>(std::move(picture));
 
   canvas_picture->AssociateWithDartWrapper(dart_handle);
   return canvas_picture;
 }
 
-Picture::Picture(flutter::SkiaGPUObject<SkPicture> picture,
-                 size_t external_allocation_size)
-    : picture_(std::move(picture)),
-      external_allocation_size_(external_allocation_size) {}
+Picture::Picture(flutter::SkiaGPUObject<SkPicture> picture)
+    : picture_(std::move(picture)) {}
 
 Picture::~Picture() = default;
 
@@ -62,8 +59,7 @@ void Picture::dispose() {
 
 size_t Picture::GetAllocationSize() const {
   if (auto picture = picture_.get()) {
-    return picture->approximateBytesUsed() + sizeof(Picture) +
-           external_allocation_size_;
+    return picture->approximateBytesUsed() + sizeof(Picture);
   } else {
     return sizeof(Picture);
   }

lib/ui/painting/picture.h

@@ -25,8 +25,7 @@ class Picture : public RefCountedDartWrappable<Picture> {
  public:
   ~Picture() override;
   static fml::RefPtr<Picture> Create(Dart_Handle dart_handle,
-                                     flutter::SkiaGPUObject<SkPicture> picture,
-                                     size_t external_allocation_size);
+                                     flutter::SkiaGPUObject<SkPicture> picture);
 
   sk_sp<SkPicture> picture() const { return picture_.get(); }
 
@@ -45,14 +44,10 @@ class Picture : public RefCountedDartWrappable<Picture> {
                                       uint32_t height,
                                       Dart_Handle raw_image_callback);
 
-  size_t external_allocation_size() const { return external_allocation_size_; }
-
  private:
-  Picture(flutter::SkiaGPUObject<SkPicture> picture,
-          size_t external_allocation_size_);
+  Picture(flutter::SkiaGPUObject<SkPicture> picture);
 
   flutter::SkiaGPUObject<SkPicture> picture_;
-  size_t external_allocation_size_;
 };
 
 }  // namespace flutter

lib/ui/painting/picture_recorder.cc

@@ -47,11 +47,9 @@ fml::RefPtr<Picture> PictureRecorder::endRecording(Dart_Handle dart_picture) {
     return nullptr;
   }
 
-  fml::RefPtr<Picture> picture =
-      Picture::Create(dart_picture,
-                      UIDartState::CreateGPUObject(
-                          picture_recorder_.finishRecordingAsPicture()),
-                      canvas_->external_allocation_size());
+  fml::RefPtr<Picture> picture = Picture::Create(
+      dart_picture, UIDartState::CreateGPUObject(
+                        picture_recorder_.finishRecordingAsPicture()));
 
   canvas_->Invalidate();
   canvas_ = nullptr;

lib/ui/ui_dart_state.cc

@@ -18,6 +18,7 @@ UIDartState::UIDartState(
     TaskObserverAdd add_callback,
     TaskObserverRemove remove_callback,
     fml::WeakPtr<SnapshotDelegate> snapshot_delegate,
+    fml::WeakPtr<HintFreedDelegate> hint_freed_delegate,
     fml::WeakPtr<IOManager> io_manager,
     fml::RefPtr<SkiaUnrefQueue> skia_unref_queue,
     fml::WeakPtr<ImageDecoder> image_decoder,
@@ -31,6 +32,7 @@ UIDartState::UIDartState(
       add_callback_(std::move(add_callback)),
       remove_callback_(std::move(remove_callback)),
       snapshot_delegate_(std::move(snapshot_delegate)),
+      hint_freed_delegate_(std::move(hint_freed_delegate)),
       io_manager_(std::move(io_manager)),
       skia_unref_queue_(std::move(skia_unref_queue)),
       image_decoder_(std::move(image_decoder)),
@@ -136,6 +138,10 @@ fml::WeakPtr<SnapshotDelegate> UIDartState::GetSnapshotDelegate() const {
   return snapshot_delegate_;
 }
 
+fml::WeakPtr<HintFreedDelegate> UIDartState::GetHintFreedDelegate() const {
+  return hint_freed_delegate_;
+}
+
 fml::WeakPtr<GrDirectContext> UIDartState::GetResourceContext() const {
   if (!io_manager_) {
     return {};

lib/ui/ui_dart_state.h

@@ -15,6 +15,7 @@
 #include "flutter/fml/build_config.h"
 #include "flutter/fml/memory/weak_ptr.h"
 #include "flutter/fml/synchronization/waitable_event.h"
+#include "flutter/lib/ui/hint_freed_delegate.h"
 #include "flutter/lib/ui/io_manager.h"
 #include "flutter/lib/ui/isolate_name_server/isolate_name_server.h"
 #include "flutter/lib/ui/painting/image_decoder.h"
@@ -60,6 +61,8 @@ class UIDartState : public tonic::DartState {
 
   fml::WeakPtr<SnapshotDelegate> GetSnapshotDelegate() const;
 
+  fml::WeakPtr<HintFreedDelegate> GetHintFreedDelegate() const;
+
   fml::WeakPtr<GrDirectContext> GetResourceContext() const;
 
   fml::WeakPtr<ImageDecoder> GetImageDecoder() const;
@@ -87,6 +90,7 @@ class UIDartState : public tonic::DartState {
               TaskObserverAdd add_callback,
               TaskObserverRemove remove_callback,
               fml::WeakPtr<SnapshotDelegate> snapshot_delegate,
+              fml::WeakPtr<HintFreedDelegate> hint_freed_delegate,
               fml::WeakPtr<IOManager> io_manager,
               fml::RefPtr<SkiaUnrefQueue> skia_unref_queue,
               fml::WeakPtr<ImageDecoder> image_decoder,
@@ -113,6 +117,7 @@ class UIDartState : public tonic::DartState {
   const TaskObserverAdd add_callback_;
   const TaskObserverRemove remove_callback_;
   fml::WeakPtr<SnapshotDelegate> snapshot_delegate_;
+  fml::WeakPtr<HintFreedDelegate> hint_freed_delegate_;
   fml::WeakPtr<IOManager> io_manager_;
   fml::RefPtr<SkiaUnrefQueue> skia_unref_queue_;
   fml::WeakPtr<ImageDecoder> image_decoder_;

runtime/dart_isolate.cc

@@ -58,6 +58,7 @@ std::weak_ptr<DartIsolate> DartIsolate::CreateRootIsolate(
     TaskRunners task_runners,
     std::unique_ptr<PlatformConfiguration> platform_configuration,
     fml::WeakPtr<SnapshotDelegate> snapshot_delegate,
+    fml::WeakPtr<HintFreedDelegate> hint_freed_delegate,
     fml::WeakPtr<IOManager> io_manager,
     fml::RefPtr<SkiaUnrefQueue> unref_queue,
     fml::WeakPtr<ImageDecoder> image_decoder,
@@ -84,15 +85,16 @@ std::weak_ptr<DartIsolate> DartIsolate::CreateRootIsolate(
 
   auto isolate_data = std::make_unique<std::shared_ptr<DartIsolate>>(
       std::shared_ptr<DartIsolate>(new DartIsolate(
-          settings,                      // settings
-          task_runners,                  // task runners
-          std::move(snapshot_delegate),  // snapshot delegate
-          std::move(io_manager),         // IO manager
-          std::move(unref_queue),        // Skia unref queue
-          std::move(image_decoder),      // Image Decoder
-          advisory_script_uri,           // advisory URI
-          advisory_script_entrypoint,    // advisory entrypoint
-          true                           // is_root_isolate
+          settings,                        // settings
+          task_runners,                    // task runners
+          std::move(snapshot_delegate),    // snapshot delegate
+          std::move(hint_freed_delegate),  // hint freed delegate
+          std::move(io_manager),           // IO manager
+          std::move(unref_queue),          // Skia unref queue
+          std::move(image_decoder),        // Image Decoder
+          advisory_script_uri,             // advisory URI
+          advisory_script_entrypoint,      // advisory entrypoint
+          true                             // is_root_isolate
           )));
 
   DartErrorString error;
@@ -120,6 +122,7 @@ std::weak_ptr<DartIsolate> DartIsolate::CreateRootIsolate(
 DartIsolate::DartIsolate(const Settings& settings,
                          TaskRunners task_runners,
                          fml::WeakPtr<SnapshotDelegate> snapshot_delegate,
+                         fml::WeakPtr<HintFreedDelegate> hint_freed_delegate,
                          fml::WeakPtr<IOManager> io_manager,
                          fml::RefPtr<SkiaUnrefQueue> unref_queue,
                          fml::WeakPtr<ImageDecoder> image_decoder,
@@ -130,6 +133,7 @@ DartIsolate::DartIsolate(const Settings& settings,
                   settings.task_observer_add,
                   settings.task_observer_remove,
                   std::move(snapshot_delegate),
+                  std::move(hint_freed_delegate),
                   std::move(io_manager),
                   std::move(unref_queue),
                   std::move(image_decoder),
@@ -603,6 +607,7 @@ Dart_Isolate DartIsolate::DartCreateAndStartServiceIsolate(
           null_task_runners,              // task runners
           nullptr,                        // platform_configuration
           {},                             // snapshot delegate
+          {},                             // Hint freed delegate
           {},                             // IO Manager
           {},                             // Skia unref queue
           {},                             // Image Decoder
@@ -706,6 +711,7 @@ Dart_Isolate DartIsolate::DartIsolateGroupCreateCallback(
           (*isolate_group_data)->GetSettings(),  // settings
           null_task_runners,                     // task_runners
           fml::WeakPtr<SnapshotDelegate>{},      // snapshot_delegate
+          fml::WeakPtr<HintFreedDelegate>{},     // hint_freed_delegate
           fml::WeakPtr<IOManager>{},             // io_manager
           fml::RefPtr<SkiaUnrefQueue>{},         // unref_queue
           fml::WeakPtr<ImageDecoder>{},          // image_decoder
@@ -749,6 +755,7 @@ bool DartIsolate::DartIsolateInitializeCallback(void** child_callback_data,
           (*isolate_group_data)->GetSettings(),           // settings
           null_task_runners,                              // task_runners
           fml::WeakPtr<SnapshotDelegate>{},               // snapshot_delegate
+          fml::WeakPtr<HintFreedDelegate>{},              // hint_freed_delegate
           fml::WeakPtr<IOManager>{},                      // io_manager
           fml::RefPtr<SkiaUnrefQueue>{},                  // unref_queue
           fml::WeakPtr<ImageDecoder>{},                   // image_decoder

runtime/dart_isolate.h

@@ -13,6 +13,7 @@
 #include "flutter/fml/compiler_specific.h"
 #include "flutter/fml/macros.h"
 #include "flutter/fml/mapping.h"
+#include "flutter/lib/ui/hint_freed_delegate.h"
 #include "flutter/lib/ui/io_manager.h"
 #include "flutter/lib/ui/snapshot_delegate.h"
 #include "flutter/lib/ui/ui_dart_state.h"
@@ -194,6 +195,7 @@ class DartIsolate : public UIDartState {
       TaskRunners task_runners,
       std::unique_ptr<PlatformConfiguration> platform_configuration,
       fml::WeakPtr<SnapshotDelegate> snapshot_delegate,
+      fml::WeakPtr<HintFreedDelegate> hint_freed_delegate,
       fml::WeakPtr<IOManager> io_manager,
       fml::RefPtr<SkiaUnrefQueue> skia_unref_queue,
       fml::WeakPtr<ImageDecoder> image_decoder,
@@ -404,6 +406,7 @@ class DartIsolate : public UIDartState {
   DartIsolate(const Settings& settings,
               TaskRunners task_runners,
               fml::WeakPtr<SnapshotDelegate> snapshot_delegate,
+              fml::WeakPtr<HintFreedDelegate> hint_freed_delegate,
               fml::WeakPtr<IOManager> io_manager,
               fml::RefPtr<SkiaUnrefQueue> unref_queue,
               fml::WeakPtr<ImageDecoder> image_decoder,

runtime/dart_isolate_unittests.cc

@@ -51,6 +51,7 @@ TEST_F(DartIsolateTest, RootIsolateCreationAndShutdown) {
       std::move(task_runners),            // task runners
       nullptr,                            // window
       {},                                 // snapshot delegate
+      {},                                 // hint freed delegate
       {},                                 // io manager
       {},                                 // unref queue
       {},                                 // image decoder
@@ -85,6 +86,7 @@ TEST_F(DartIsolateTest, IsolateShutdownCallbackIsInIsolateScope) {
       std::move(task_runners),            // task runners
       nullptr,                            // window
       {},                                 // snapshot delegate
+      {},                                 // hint freed delegate
       {},                                 // io manager
       {},                                 // unref queue
       {},                                 // image decoder

runtime/dart_lifecycle_unittests.cc

@@ -56,6 +56,7 @@ static std::shared_ptr<DartIsolate> CreateAndRunRootIsolate(
       runners,                            // task_runners
       {},                                 // window
       {},                                 // snapshot_delegate
+      {},                                 // hint_freed_delegate
       {},                                 // io_manager
       {},                                 // unref_queue
       {},                                 // image_decoder