Revert "Introduce a delegate class for gpu metal rendering (#22611)" (#22775)

This reverts commit 5bf65335.

ci/licenses_golden/licenses_flutter

@@ -673,8 +673,6 @@ FILE: ../../../flutter/shell/gpu/gpu_surface_gl_delegate.cc
 FILE: ../../../flutter/shell/gpu/gpu_surface_gl_delegate.h
 FILE: ../../../flutter/shell/gpu/gpu_surface_metal.h
 FILE: ../../../flutter/shell/gpu/gpu_surface_metal.mm
-FILE: ../../../flutter/shell/gpu/gpu_surface_metal_delegate.cc
-FILE: ../../../flutter/shell/gpu/gpu_surface_metal_delegate.h
 FILE: ../../../flutter/shell/gpu/gpu_surface_software.cc
 FILE: ../../../flutter/shell/gpu/gpu_surface_software.h
 FILE: ../../../flutter/shell/gpu/gpu_surface_software_delegate.cc
@@ -934,8 +932,6 @@ FILE: ../../../flutter/shell/platform/darwin/common/framework/Source/FlutterStan
 FILE: ../../../flutter/shell/platform/darwin/common/framework/Source/FlutterStandardCodec_Internal.h
 FILE: ../../../flutter/shell/platform/darwin/common/framework/Source/flutter_codecs_unittest.mm
 FILE: ../../../flutter/shell/platform/darwin/common/framework/Source/flutter_standard_codec_unittest.mm
-FILE: ../../../flutter/shell/platform/darwin/graphics/FlutterDarwinContextMetal.h
-FILE: ../../../flutter/shell/platform/darwin/graphics/FlutterDarwinContextMetal.mm
 FILE: ../../../flutter/shell/platform/darwin/ios/framework/Flutter.podspec
 FILE: ../../../flutter/shell/platform/darwin/ios/framework/Headers/Flutter.h
 FILE: ../../../flutter/shell/platform/darwin/ios/framework/Headers/FlutterAppDelegate.h

shell/common/animator.cc

@@ -29,9 +29,9 @@ Animator::Animator(Delegate& delegate,
       last_vsync_start_time_(),
       last_frame_target_time_(),
       dart_frame_deadline_(0),
-#if SHELL_ENABLE_METAL
+#if FLUTTER_SHELL_ENABLE_METAL
       layer_tree_pipeline_(fml::MakeRefCounted<LayerTreePipeline>(2)),
-#else   // SHELL_ENABLE_METAL
+#else   // FLUTTER_SHELL_ENABLE_METAL
       // TODO(dnfield): We should remove this logic and set the pipeline depth
       // back to 2 in this case. See
       // https://github.com/flutter/engine/pull/9132 for discussion.
@@ -40,7 +40,7 @@ Animator::Animator(Delegate& delegate,
                   task_runners.GetRasterTaskRunner()
               ? 1
               : 2)),
-#endif  // SHELL_ENABLE_METAL
+#endif  // FLUTTER_SHELL_ENABLE_METAL
       pending_frame_semaphore_(1),
       frame_number_(1),
       paused_(false),

shell/gpu/BUILD.gn

@@ -51,8 +51,6 @@ source_set("gpu_surface_metal") {
   sources = [
     "gpu_surface_metal.h",
     "gpu_surface_metal.mm",
-    "gpu_surface_metal_delegate.cc",
-    "gpu_surface_metal_delegate.h",
   ]
 
   deps = gpu_common_deps

shell/gpu/gpu_surface_metal.h

@@ -5,30 +5,35 @@
 #ifndef FLUTTER_SHELL_GPU_GPU_SURFACE_METAL_H_
 #define FLUTTER_SHELL_GPU_GPU_SURFACE_METAL_H_
 
+#include <Metal/Metal.h>
+
 #include "flutter/flow/surface.h"
 #include "flutter/fml/macros.h"
-#include "flutter/shell/gpu/gpu_surface_metal_delegate.h"
+#include "flutter/fml/platform/darwin/scoped_nsobject.h"
 #include "third_party/skia/include/gpu/GrDirectContext.h"
 #include "third_party/skia/include/gpu/mtl/GrMtlTypes.h"
 
+@class CAMetalLayer;
+
 namespace flutter {
 
 class SK_API_AVAILABLE_CA_METAL_LAYER GPUSurfaceMetal : public Surface {
  public:
-  GPUSurfaceMetal(GPUSurfaceMetalDelegate* delegate,
-                  sk_sp<GrDirectContext> context);
+  GPUSurfaceMetal(fml::scoped_nsobject<CAMetalLayer> layer,
+                  sk_sp<GrDirectContext> context,
+                  fml::scoped_nsprotocol<id<MTLCommandQueue>> command_queue);
 
   // |Surface|
   ~GPUSurfaceMetal();
 
-  // |Surface|
-  bool IsValid() override;
-
  private:
-  const GPUSurfaceMetalDelegate* delegate_;
-  const MTLRenderTargetType render_target_type_;
-  GrMTLHandle next_drawable_ = nullptr;
+  fml::scoped_nsobject<CAMetalLayer> layer_;
   sk_sp<GrDirectContext> context_;
+  fml::scoped_nsprotocol<id<MTLCommandQueue>> command_queue_;
+  GrMTLHandle next_drawable_ = nullptr;
+
+  // |Surface|
+  bool IsValid() override;
 
   // |Surface|
   std::unique_ptr<SurfaceFrame> AcquireFrame(const SkISize& size) override;
@@ -42,12 +47,6 @@ class SK_API_AVAILABLE_CA_METAL_LAYER GPUSurfaceMetal : public Surface {
   // |Surface|
   std::unique_ptr<GLContextResult> MakeRenderContextCurrent() override;
 
-  std::unique_ptr<SurfaceFrame> AcquireFrameFromCAMetalLayer(
-      const SkISize& frame_info);
-
-  std::unique_ptr<SurfaceFrame> AcquireFrameFromMTLTexture(
-      const SkISize& frame_info);
-
   void ReleaseUnusedDrawableIfNecessary();
 
   FML_DISALLOW_COPY_AND_ASSIGN(GPUSurfaceMetal);

shell/gpu/gpu_surface_metal.mm

@@ -4,12 +4,9 @@
 
 #include "flutter/shell/gpu/gpu_surface_metal.h"
 
-#import <Metal/Metal.h>
+#include <QuartzCore/CAMetalLayer.h>
 
-#include "flutter/fml/make_copyable.h"
-#include "flutter/fml/platform/darwin/cf_utils.h"
 #include "flutter/fml/trace_event.h"
-#include "flutter/shell/gpu/gpu_surface_metal_delegate.h"
 #include "third_party/skia/include/core/SkSurface.h"
 #include "third_party/skia/include/gpu/GrBackendSurface.h"
 #include "third_party/skia/include/ports/SkCFObject.h"
@@ -18,10 +15,17 @@ static_assert(!__has_feature(objc_arc), "ARC must be disabled.");
 
 namespace flutter {
 
-GPUSurfaceMetal::GPUSurfaceMetal(GPUSurfaceMetalDelegate* delegate, sk_sp<GrDirectContext> context)
-    : delegate_(delegate),
-      render_target_type_(delegate->GetRenderTargetType()),
-      context_(std::move(context)) {}
+GPUSurfaceMetal::GPUSurfaceMetal(fml::scoped_nsobject<CAMetalLayer> layer,
+                                 sk_sp<GrDirectContext> context,
+                                 fml::scoped_nsprotocol<id<MTLCommandQueue>> command_queue)
+    : layer_(std::move(layer)),
+      context_(std::move(context)),
+      command_queue_(std::move(command_queue)) {
+  layer_.get().pixelFormat = MTLPixelFormatBGRA8Unorm;
+  // Flutter needs to read from the color attachment in cases where there are effects such as
+  // backdrop filters.
+  layer_.get().framebufferOnly = NO;
+}
 
 GPUSurfaceMetal::~GPUSurfaceMetal() {
   ReleaseUnusedDrawableIfNecessary();
@@ -29,7 +33,7 @@ GPUSurfaceMetal::~GPUSurfaceMetal() {
 
 // |Surface|
 bool GPUSurfaceMetal::IsValid() {
-  return context_ != nullptr;
+  return layer_ && context_ && command_queue_;
 }
 
 // |Surface|
@@ -44,30 +48,21 @@ std::unique_ptr<SurfaceFrame> GPUSurfaceMetal::AcquireFrame(const SkISize& frame
     return nullptr;
   }
 
-  switch (render_target_type_) {
-    case MTLRenderTargetType::kCAMetalLayer:
-      return AcquireFrameFromCAMetalLayer(frame_size);
-    case MTLRenderTargetType::kMTLTexture:
-      return AcquireFrameFromMTLTexture(frame_size);
-    default:
-      FML_CHECK(false) << "Unknown MTLRenderTargetType type.";
-  }
-
-  return nullptr;
-}
+  const auto drawable_size = CGSizeMake(frame_size.width(), frame_size.height());
 
-std::unique_ptr<SurfaceFrame> GPUSurfaceMetal::AcquireFrameFromCAMetalLayer(
-    const SkISize& frame_info) {
-  auto layer = delegate_->GetCAMetalLayer(frame_info);
-  if (!layer) {
-    FML_LOG(ERROR) << "Invalid CAMetalLayer given by the embedder.";
-    return nullptr;
+  if (!CGSizeEqualToSize(drawable_size, layer_.get().drawableSize)) {
+    layer_.get().drawableSize = drawable_size;
   }
 
   ReleaseUnusedDrawableIfNecessary();
-  sk_sp<SkSurface> surface =
-      SkSurface::MakeFromCAMetalLayer(context_.get(),            // context
-                                      layer,                     // layer
+
+  // When there are platform views in the scene, the drawable needs to be presented in the same
+  // transaction as the one created for platform views. When the drawable are being presented from
+  // the raster thread, there is no such transaction.
+  layer_.get().presentsWithTransaction = [[NSThread currentThread] isMainThread];
+
+  auto surface = SkSurface::MakeFromCAMetalLayer(context_.get(),            // context
+                                                 layer_.get(),              // layer
                                                  kTopLeft_GrSurfaceOrigin,  // origin
                                                  1,                         // sample count
                                                  kBGRA_8888_SkColorType,    // color type
@@ -77,13 +72,11 @@ std::unique_ptr<SurfaceFrame> GPUSurfaceMetal::AcquireFrameFromCAMetalLayer(
   );
 
   if (!surface) {
-    FML_LOG(ERROR) << "Could not create the SkSurface from the CAMetalLayer.";
+    FML_LOG(ERROR) << "Could not create the SkSurface from the metal texture.";
     return nullptr;
   }
 
-  auto submit_callback =
-      fml::MakeCopyable([drawable = next_drawable_, delegate = delegate_](
-                            const SurfaceFrame& surface_frame, SkCanvas* canvas) -> bool {
+  auto submit_callback = [this](const SurfaceFrame& surface_frame, SkCanvas* canvas) -> bool {
     TRACE_EVENT0("flutter", "GPUSurfaceMetal::Submit");
     if (canvas == nullptr) {
       FML_DLOG(ERROR) << "Canvas not available.";
@@ -92,51 +85,23 @@ std::unique_ptr<SurfaceFrame> GPUSurfaceMetal::AcquireFrameFromCAMetalLayer(
 
     canvas->flush();
 
-        if (!drawable) {
-          FML_DLOG(ERROR) << "Unable to obtain a metal drawable.";
+    if (next_drawable_ == nullptr) {
+      FML_DLOG(ERROR) << "Could not acquire next Metal drawable from the SkSurface.";
       return false;
     }
 
-        return delegate->PresentDrawable(drawable);
-      });
-
-  return std::make_unique<SurfaceFrame>(std::move(surface), true, submit_callback);
-}
-
-std::unique_ptr<SurfaceFrame> GPUSurfaceMetal::AcquireFrameFromMTLTexture(
-    const SkISize& frame_info) {
-  GPUMTLTextureInfo texture = delegate_->GetMTLTexture(frame_info);
-  id<MTLTexture> mtl_texture = (id<MTLTexture>)(texture.texture);
-
-  if (!mtl_texture) {
-    FML_LOG(ERROR) << "Invalid MTLTexture given by the embedder.";
-    return nullptr;
-  }
-
-  GrMtlTextureInfo info;
-  info.fTexture.reset([mtl_texture retain]);
-  GrBackendTexture backend_texture(frame_info.width(), frame_info.height(), GrMipmapped::kNo, info);
-
-  sk_sp<SkSurface> surface =
-      SkSurface::MakeFromBackendTexture(context_.get(), backend_texture, kTopLeft_GrSurfaceOrigin,
-                                        1, kBGRA_8888_SkColorType, nullptr, nullptr);
+    auto command_buffer =
+        fml::scoped_nsprotocol<id<MTLCommandBuffer>>([[command_queue_.get() commandBuffer] retain]);
 
-  if (!surface) {
-    FML_LOG(ERROR) << "Could not create the SkSurface from the metal texture.";
-    return nullptr;
-  }
-
-  auto submit_callback = [texture_id = texture.texture_id, delegate = delegate_](
-                             const SurfaceFrame& surface_frame, SkCanvas* canvas) -> bool {
-    TRACE_EVENT0("flutter", "GPUSurfaceMetal::PresentTexture");
-    if (canvas == nullptr) {
-      FML_DLOG(ERROR) << "Canvas not available.";
-      return false;
-    }
+    fml::scoped_nsprotocol<id<CAMetalDrawable>> drawable(
+        reinterpret_cast<id<CAMetalDrawable>>(next_drawable_));
+    next_drawable_ = nullptr;
 
-    canvas->flush();
+    [command_buffer.get() commit];
+    [command_buffer.get() waitUntilScheduled];
+    [drawable.get() present];
 
-    return delegate->PresentTexture(texture_id);
+    return true;
   };
 
   return std::make_unique<SurfaceFrame>(std::move(surface), true, submit_callback);

shell/gpu/gpu_surface_metal_delegate.cc

-// 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.
-
-#include "flutter/shell/gpu/gpu_surface_metal_delegate.h"
-
-namespace flutter {
-
-GPUSurfaceMetalDelegate::GPUSurfaceMetalDelegate(
-    MTLRenderTargetType render_target_type)
-    : render_target_type_(render_target_type) {}
-
-GPUSurfaceMetalDelegate::~GPUSurfaceMetalDelegate() = default;
-
-MTLRenderTargetType GPUSurfaceMetalDelegate::GetRenderTargetType() {
-  return render_target_type_;
-}
-
-}  // namespace flutter

shell/gpu/gpu_surface_metal_delegate.h

-// 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_SHELL_GPU_GPU_SURFACE_METAL_DELEGATE_H_
-#define FLUTTER_SHELL_GPU_GPU_SURFACE_METAL_DELEGATE_H_
-
-#include <stdint.h>
-
-#include "flutter/fml/macros.h"
-#include "third_party/skia/include/core/SkSize.h"
-#include "third_party/skia/include/core/SkSurface.h"
-#include "third_party/skia/include/gpu/mtl/GrMtlTypes.h"
-
-namespace flutter {
-
-// expected to be id<MTLDevice>
-typedef void* GPUMTLDeviceHandle;
-
-// expected to be id<MTLCommandQueues>
-typedef void* GPUMTLCommandQueueHandle;
-
-// expected to be CAMetalLayer*
-typedef void* GPUCAMetalLayerHandle;
-
-// expected to be id<MTLTexture>
-typedef void* GPUMTLTextureHandle;
-
-struct GPUMTLTextureInfo {
-  intptr_t texture_id;
-  GPUMTLTextureHandle texture;
-};
-
-enum class MTLRenderTargetType { kMTLTexture, kCAMetalLayer };
-
-//------------------------------------------------------------------------------
-/// @brief      Interface implemented by all platform surfaces that can present
-///             a metal backing store to the "screen". The GPU surface
-///             abstraction (which abstracts the client rendering API) uses this
-///             delegation pattern to tell the platform surface (which abstracts
-///             how backing stores fulfilled by the selected client rendering
-///             API end up on the "screen" on a particular platform) when the
-///             rasterizer needs to allocate and present the software backing
-///             store.
-///
-/// @see        |IOSurfaceMetal| and |EmbedderSurfaceMetal|.
-///
-class GPUSurfaceMetalDelegate {
- public:
-  //------------------------------------------------------------------------------
-  /// @brief Construct a new GPUSurfaceMetalDelegate object with the specified
-  /// render_target type.
-  ///
-  /// @see |MTLRenderTargetType|
-  ///
-  explicit GPUSurfaceMetalDelegate(MTLRenderTargetType render_target);
-
-  virtual ~GPUSurfaceMetalDelegate();
-
-  //------------------------------------------------------------------------------
-  /// @brief Returns the handle to the CAMetalLayer to render to. This is only
-  /// called when the specifed render target type is `kCAMetalLayer`.
-  ///
-  virtual GPUCAMetalLayerHandle GetCAMetalLayer(
-      const SkISize& frame_info) const = 0;
-
-  //------------------------------------------------------------------------------
-  /// @brief Presents the drawable to the "screen". The drawable is obtained
-  /// from the CAMetalLayer that given by `GetCAMetalLayer` call. This is only
-  /// called when the specified render target type in `kCAMetalLayer`.
-  ///
-  /// @see |GPUSurfaceMetalDelegate::GetCAMetalLayer|
-  ///
-  virtual bool PresentDrawable(GrMTLHandle drawable) const = 0;
-
-  //------------------------------------------------------------------------------
-  /// @brief Returns the handle to the MTLTexture to render to. This is only
-  /// called when the specefied render target type is `kMTLTexture`.
-  ///
-  virtual GPUMTLTextureInfo GetMTLTexture(const SkISize& frame_info) const = 0;
-
-  //------------------------------------------------------------------------------
-  /// @brief Presents the texture with `texture_id` to the "screen".
-  /// `texture_id` corresponds to a texture that has been obtained by an earlier
-  /// call to `GetMTLTexture`. This is only called when the specefied render
-  /// target type is `kMTLTexture`.
-  ///
-  /// @see |GPUSurfaceMetalDelegate::GetMTLTexture|
-  ///
-  virtual bool PresentTexture(intptr_t texture_id) const = 0;
-
-  MTLRenderTargetType GetRenderTargetType();
-
- private:
-  const MTLRenderTargetType render_target_type_;
-};
-
-}  // namespace flutter
-
-#endif  // FLUTTER_SHELL_GPU_GPU_SURFACE_METAL_DELEGATE_H_

shell/platform/darwin/graphics/BUILD.gn

-# 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.
-
-assert(is_ios || is_mac)
-
-import("//flutter/common/config.gni")
-
-source_set("graphics") {
-  cflags_objc = flutter_cflags_objc
-  cflags_objcc = flutter_cflags_objcc
-
-  sources = [
-    "FlutterDarwinContextMetal.h",
-    "FlutterDarwinContextMetal.mm",
-  ]
-
-  deps = [
-    "//flutter/common/graphics",
-    "//flutter/fml",
-  ]
-
-  public_deps = [ "//third_party/skia" ]
-
-  public_configs = [ "//flutter:config" ]
-}

shell/platform/darwin/graphics/FlutterDarwinContextMetal.h

-// 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 SHELL_PLATFORM_DARWIN_GRAPHICS_DARWIN_CONTEXT_METAL_H_
-#define SHELL_PLATFORM_DARWIN_GRAPHICS_DARWIN_CONTEXT_METAL_H_
-
-#import <Foundation/Foundation.h>
-#import <Metal/Metal.h>
-
-#include "third_party/skia/include/gpu/GrDirectContext.h"
-
-NS_ASSUME_NONNULL_BEGIN
-
-/**
- * Provides skia GrContexts that are shared between iOS and macOS embeddings.
- */
-@interface FlutterDarwinContextMetal : NSObject
-
-/**
- * Initializes a FlutterDarwinContextMetal with the system default MTLDevice and a new
- * MTLCommandQueue.
- */
-- (instancetype)initWithDefaultMTLDevice;
-
-/**
- * Initializes a FlutterDarwinContextMetal with provided MTLDevice and MTLCommandQueue.
- */
-- (instancetype)initWithMTLDevice:(id<MTLDevice>)mtlDevice
-                     commandQueue:(id<MTLCommandQueue>)commandQueue;
-
-/**
- * MTLDevice that is backing this context.s
- */
-@property(nonatomic, readonly) id<MTLDevice> mtlDevice;
-
-/**
- * MTLCommandQueue that is acquired from the `mtlDevice`. This queue is used both for rendering and
- * resource related commands.
- */
-@property(nonatomic, readonly) id<MTLCommandQueue> mtlCommandQueue;
-
-/**
- * Skia GrContext that is used for rendering.
- */
-@property(nonatomic, readonly) sk_sp<GrDirectContext> mainContext;
-
-/**
- * Skia GrContext that is used for resources (uploading textures etc).
- */
-@property(nonatomic, readonly) sk_sp<GrDirectContext> resourceContext;
-
-@end
-
-NS_ASSUME_NONNULL_END
-
-#endif  // SHELL_PLATFORM_DARWIN_GRAPHICS_DARWIN_CONTEXT_METAL_H_

shell/platform/darwin/graphics/FlutterDarwinContextMetal.mm

-// 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.
-
-#import "flutter/shell/platform/darwin/graphics/FlutterDarwinContextMetal.h"
-
-#include "flutter/common/graphics/persistent_cache.h"
-#include "flutter/fml/logging.h"
-#include "third_party/skia/include/gpu/GrContextOptions.h"
-
-static GrContextOptions CreateMetalGrContextOptions() {
-  GrContextOptions options = {};
-  if (flutter::PersistentCache::cache_sksl()) {
-    options.fShaderCacheStrategy = GrContextOptions::ShaderCacheStrategy::kSkSL;
-  }
-  flutter::PersistentCache::MarkStrategySet();
-  options.fPersistentCache = flutter::PersistentCache::GetCacheForProcess();
-  return options;
-}
-
-@implementation FlutterDarwinContextMetal
-
-- (instancetype)initWithDefaultMTLDevice {
-  id<MTLDevice> mtlDevice = MTLCreateSystemDefaultDevice();
-  return [self initWithMTLDevice:mtlDevice commandQueue:[mtlDevice newCommandQueue]];
-}
-
-- (instancetype)initWithMTLDevice:(id<MTLDevice>)mtlDevice
-                     commandQueue:(id<MTLCommandQueue>)commandQueue {
-  self = [super init];
-  if (self != nil) {
-    _mtlDevice = mtlDevice;
-
-    if (!_mtlDevice) {
-      FML_DLOG(ERROR) << "Could not acquire Metal device.";
-      [self release];
-      return nil;
-    }
-
-    _mtlCommandQueue = commandQueue;
-
-    if (!_mtlCommandQueue) {
-      FML_DLOG(ERROR) << "Could not create Metal command queue.";
-      [self release];
-      return nil;
-    }
-
-    [_mtlCommandQueue setLabel:@"Flutter Main Queue"];
-
-    auto contextOptions = CreateMetalGrContextOptions();
-
-    // Skia expect arguments to `MakeMetal` transfer ownership of the reference in for release later
-    // when the GrDirectContext is collected.
-    _mainContext =
-        GrDirectContext::MakeMetal([_mtlDevice retain], [_mtlCommandQueue retain], contextOptions);
-    _resourceContext =
-        GrDirectContext::MakeMetal([_mtlDevice retain], [_mtlCommandQueue retain], contextOptions);
-
-    if (!_mainContext || !_resourceContext) {
-      FML_DLOG(ERROR) << "Could not create Skia Metal contexts.";
-      [self release];
-      return nil;
-    }
-
-    _resourceContext->setResourceCacheLimits(0u, 0u);
-  }
-  return self;
-}
-
-@end

shell/platform/darwin/ios/BUILD.gn

@@ -42,8 +42,6 @@ source_set("flutter_framework_source") {
   cflags_objc = flutter_cflags_objc
   cflags_objcc = flutter_cflags_objcc
 
-  deps = []
-
   sources = [
     "framework/Source/FlutterAppDelegate.mm",
     "framework/Source/FlutterBinaryMessengerRelay.mm",
@@ -118,6 +116,8 @@ source_set("flutter_framework_source") {
   defines = [ "FLUTTER_FRAMEWORK=1" ]
 
   if (shell_enable_metal) {
+    defines += [ "FLUTTER_SHELL_ENABLE_METAL=1" ]
+
     sources += [
       "ios_context_metal.h",
       "ios_context_metal.mm",
@@ -126,11 +126,9 @@ source_set("flutter_framework_source") {
       "ios_surface_metal.h",
       "ios_surface_metal.mm",
     ]
-
-    deps += [ "//flutter/shell/platform/darwin/graphics" ]
   }
 
-  deps += [
+  deps = [
     ":ios_gpu_configuration",
     "//flutter/common",
     "//flutter/common/graphics",
@@ -146,10 +144,7 @@ source_set("flutter_framework_source") {
     "//third_party/skia",
   ]
 
-  public_configs = [
-    ":ios_gpu_configuration_config",
-    "//flutter:config",
-  ]
+  public_configs = [ "//flutter:config" ]
 
   libs = [
     "AudioToolbox.framework",
@@ -224,7 +219,6 @@ shared_library("ios_test_flutter") {
   ]
   deps = [
     ":flutter_framework_source",
-    ":ios_gpu_configuration",
     ":ios_test_flutter_mrc",
     "//flutter/common:common",
     "//flutter/shell/platform/darwin/common:framework_shared",
@@ -234,10 +228,7 @@ shared_library("ios_test_flutter") {
     "//third_party/rapidjson",
     "//third_party/skia",
   ]
-  public_configs = [
-    ":ios_gpu_configuration_config",
-    "//flutter:config",
-  ]
+  public_configs = [ "//flutter:config" ]
 }
 
 shared_library("create_flutter_framework_dylib") {

shell/platform/darwin/ios/ios_context.mm

@@ -8,9 +8,9 @@
 #import "flutter/shell/platform/darwin/ios/ios_context_gl.h"
 #import "flutter/shell/platform/darwin/ios/ios_context_software.h"
 
-#if SHELL_ENABLE_METAL
+#if FLUTTER_SHELL_ENABLE_METAL
 #import "flutter/shell/platform/darwin/ios/ios_context_metal.h"
-#endif  // SHELL_ENABLE_METAL
+#endif  // FLUTTER_SHELL_ENABLE_METAL
 
 namespace flutter {
 
@@ -24,10 +24,10 @@ std::unique_ptr<IOSContext> IOSContext::Create(IOSRenderingAPI rendering_api) {
       return std::make_unique<IOSContextGL>();
     case IOSRenderingAPI::kSoftware:
       return std::make_unique<IOSContextSoftware>();
-#if SHELL_ENABLE_METAL
+#if FLUTTER_SHELL_ENABLE_METAL
     case IOSRenderingAPI::kMetal:
       return std::make_unique<IOSContextMetal>();
-#endif  // SHELL_ENABLE_METAL
+#endif  // FLUTTER_SHELL_ENABLE_METAL
     default:
       break;
   }

shell/platform/darwin/ios/ios_context_metal.h

@@ -10,7 +10,6 @@
 #include "flutter/fml/macros.h"
 #include "flutter/fml/platform/darwin/cf_utils.h"
 #include "flutter/fml/platform/darwin/scoped_nsobject.h"
-#import "flutter/shell/platform/darwin/graphics/FlutterDarwinContextMetal.h"
 #import "flutter/shell/platform/darwin/ios/ios_context.h"
 #include "third_party/skia/include/gpu/GrDirectContext.h"
 
@@ -22,15 +21,21 @@ class IOSContextMetal final : public IOSContext {
 
   ~IOSContextMetal();
 
-  fml::scoped_nsobject<FlutterDarwinContextMetal> GetDarwinContext() const;
+  fml::scoped_nsprotocol<id<MTLDevice>> GetDevice() const;
+
+  fml::scoped_nsprotocol<id<MTLCommandQueue>> GetMainCommandQueue() const;
+
+  fml::scoped_nsprotocol<id<MTLCommandQueue>> GetResourceCommandQueue() const;
 
   sk_sp<GrDirectContext> GetMainContext() const;
 
   sk_sp<GrDirectContext> GetResourceContext() const;
 
  private:
-  fml::scoped_nsobject<FlutterDarwinContextMetal> darwin_context_metal_;
-  fml::scoped_nsprotocol<id<MTLCommandQueue>> main_command_queue_;
+  fml::scoped_nsprotocol<id<MTLDevice>> device_;
+  fml::scoped_nsprotocol<id<MTLCommandQueue>> main_queue_;
+  sk_sp<GrDirectContext> main_context_;
+  sk_sp<GrDirectContext> resource_context_;
   fml::CFRef<CVMetalTextureCacheRef> texture_cache_;
 
   // |IOSContext|

shell/platform/darwin/ios/ios_context_metal.mm

@@ -6,26 +6,57 @@
 
 #include "flutter/common/graphics/persistent_cache.h"
 #include "flutter/fml/logging.h"
-#import "flutter/shell/platform/darwin/graphics/FlutterDarwinContextMetal.h"
 #import "flutter/shell/platform/darwin/ios/ios_external_texture_metal.h"
 #include "third_party/skia/include/gpu/GrContextOptions.h"
 
 namespace flutter {
 
+static GrContextOptions CreateMetalGrContextOptions() {
+  GrContextOptions options = {};
+  if (PersistentCache::cache_sksl()) {
+    options.fShaderCacheStrategy = GrContextOptions::ShaderCacheStrategy::kSkSL;
+  }
+  PersistentCache::MarkStrategySet();
+  options.fPersistentCache = PersistentCache::GetCacheForProcess();
+  return options;
+}
+
 IOSContextMetal::IOSContextMetal() {
-  darwin_context_metal_ = fml::scoped_nsobject<FlutterDarwinContextMetal>{
-      [[[FlutterDarwinContextMetal alloc] initWithDefaultMTLDevice] retain]};
+  device_.reset([MTLCreateSystemDefaultDevice() retain]);
+  if (!device_) {
+    FML_DLOG(ERROR) << "Could not acquire Metal device.";
+    return;
+  }
+
+  main_queue_.reset([device_ newCommandQueue]);
+
+  if (!main_queue_) {
+    FML_DLOG(ERROR) << "Could not create Metal command queue.";
+    return;
+  }
+
+  [main_queue_ setLabel:@"Flutter Main Queue"];
+
+  const auto& context_options = CreateMetalGrContextOptions();
+
+  // Skia expect arguments to `MakeMetal` transfer ownership of the reference in for release later
+  // when the GrDirectContext is collected.
+  main_context_ =
+      GrDirectContext::MakeMetal([device_ retain], [main_queue_ retain], context_options);
+  resource_context_ =
+      GrDirectContext::MakeMetal([device_ retain], [main_queue_ retain], context_options);
 
-  if (!darwin_context_metal_) {
+  if (!main_context_ || !resource_context_) {
+    FML_DLOG(ERROR) << "Could not create Skia Metal contexts.";
     return;
   }
 
-  main_command_queue_.reset([darwin_context_metal_.get().mtlCommandQueue retain]);
+  resource_context_->setResourceCacheLimits(0u, 0u);
 
   CVMetalTextureCacheRef texture_cache_raw = NULL;
   auto cv_return = CVMetalTextureCacheCreate(kCFAllocatorDefault,  // allocator
                                              NULL,           // cache attributes (NULL default)
-                                             darwin_context_metal_.get().mtlDevice,  // metal device
+                                             device_.get(),  // metal device
                                              NULL,           // texture attributes (NULL default)
                                              &texture_cache_raw  // [out] cache
   );
@@ -38,21 +69,30 @@ IOSContextMetal::IOSContextMetal() {
 
 IOSContextMetal::~IOSContextMetal() = default;
 
-fml::scoped_nsobject<FlutterDarwinContextMetal> IOSContextMetal::GetDarwinContext() const {
-  return darwin_context_metal_;
+fml::scoped_nsprotocol<id<MTLDevice>> IOSContextMetal::GetDevice() const {
+  return device_;
+}
+
+fml::scoped_nsprotocol<id<MTLCommandQueue>> IOSContextMetal::GetMainCommandQueue() const {
+  return main_queue_;
+}
+
+fml::scoped_nsprotocol<id<MTLCommandQueue>> IOSContextMetal::GetResourceCommandQueue() const {
+  // TODO(52150): Create a dedicated resource queue once multiple queues are supported in Skia.
+  return main_queue_;
 }
 
 sk_sp<GrDirectContext> IOSContextMetal::GetMainContext() const {
-  return darwin_context_metal_.get().mainContext;
+  return main_context_;
 }
 
 sk_sp<GrDirectContext> IOSContextMetal::GetResourceContext() const {
-  return darwin_context_metal_.get().resourceContext;
+  return resource_context_;
 }
 
 // |IOSContext|
 sk_sp<GrDirectContext> IOSContextMetal::CreateResourceContext() {
-  return darwin_context_metal_.get().resourceContext;
+  return resource_context_;
 }
 
 // |IOSContext|

shell/platform/darwin/ios/ios_surface.mm

@@ -9,9 +9,9 @@
 
 #include "flutter/shell/platform/darwin/ios/rendering_api_selection.h"
 
-#if SHELL_ENABLE_METAL
+#if FLUTTER_SHELL_ENABLE_METAL
 #import "flutter/shell/platform/darwin/ios/ios_surface_metal.h"
-#endif  // SHELL_ENABLE_METAL
+#endif  // FLUTTER_SHELL_ENABLE_METAL
 
 namespace flutter {
 
@@ -28,7 +28,7 @@ std::unique_ptr<IOSSurface> IOSSurface::Create(std::shared_ptr<IOSContext> conte
     );
   }
 
-#if SHELL_ENABLE_METAL
+#if FLUTTER_SHELL_ENABLE_METAL
   if (@available(iOS METAL_IOS_VERSION_BASELINE, *)) {
     if ([layer.get() isKindOfClass:[CAMetalLayer class]]) {
       return std::make_unique<IOSSurfaceMetal>(
@@ -38,7 +38,7 @@ std::unique_ptr<IOSSurface> IOSSurface::Create(std::shared_ptr<IOSContext> conte
       );
     }
   }
-#endif  // SHELL_ENABLE_METAL
+#endif  // FLUTTER_SHELL_ENABLE_METAL
 
   return std::make_unique<IOSSurfaceSoftware>(std::move(layer),   // layer
                                               std::move(context)  // context

shell/platform/darwin/ios/ios_surface_metal.h

@@ -6,7 +6,6 @@
 #define FLUTTER_SHELL_PLATFORM_DARWIN_IOS_IOS_SURFACE_METAL_H_
 
 #include "flutter/fml/macros.h"
-#include "flutter/shell/gpu/gpu_surface_metal_delegate.h"
 #import "flutter/shell/platform/darwin/ios/ios_surface.h"
 #include "third_party/skia/include/gpu/mtl/GrMtlTypes.h"
 
@@ -14,8 +13,7 @@
 
 namespace flutter {
 
-class SK_API_AVAILABLE_CA_METAL_LAYER IOSSurfaceMetal final : public IOSSurface,
-                                                              public GPUSurfaceMetalDelegate {
+class SK_API_AVAILABLE_CA_METAL_LAYER IOSSurfaceMetal final : public IOSSurface {
  public:
   IOSSurfaceMetal(fml::scoped_nsobject<CAMetalLayer> layer, std::shared_ptr<IOSContext> context);
 
@@ -24,8 +22,6 @@ class SK_API_AVAILABLE_CA_METAL_LAYER IOSSurfaceMetal final : public IOSSurface,
 
  private:
   fml::scoped_nsobject<CAMetalLayer> layer_;
-  id<MTLDevice> device_;
-  id<MTLCommandQueue> command_queue_;
   bool is_valid_ = false;
 
   // |IOSSurface|
@@ -37,18 +33,6 @@ class SK_API_AVAILABLE_CA_METAL_LAYER IOSSurfaceMetal final : public IOSSurface,
   // |IOSSurface|
   std::unique_ptr<Surface> CreateGPUSurface(GrDirectContext* gr_context) override;
 
-  // |GPUSurfaceMetalDelegate|
-  GPUCAMetalLayerHandle GetCAMetalLayer(const SkISize& frame_info) const override;
-
-  // |GPUSurfaceMetalDelegate|
-  bool PresentDrawable(GrMTLHandle drawable) const override;
-
-  // |GPUSurfaceMetalDelegate|
-  GPUMTLTextureInfo GetMTLTexture(const SkISize& frame_info) const override;
-
-  // |GPUSurfaceMetalDelegate|
-  bool PresentTexture(intptr_t texture_id) const override;
-
   FML_DISALLOW_COPY_AND_ASSIGN(IOSSurfaceMetal);
 };
 

shell/platform/darwin/ios/ios_surface_metal.mm

@@ -5,8 +5,7 @@
 #import "flutter/shell/platform/darwin/ios/ios_surface_metal.h"
 
 #include "flutter/shell/gpu/gpu_surface_metal.h"
-#include "flutter/shell/gpu/gpu_surface_metal_delegate.h"
-#include "flutter/shell/platform/darwin/ios/ios_context_metal.h"
+#import "flutter/shell/platform/darwin/ios/ios_context_metal.h"
 
 namespace flutter {
 
@@ -16,14 +15,17 @@ static IOSContextMetal* CastToMetalContext(const std::shared_ptr<IOSContext>& co
 
 IOSSurfaceMetal::IOSSurfaceMetal(fml::scoped_nsobject<CAMetalLayer> layer,
                                  std::shared_ptr<IOSContext> context)
-    : IOSSurface(std::move(context)),
-      GPUSurfaceMetalDelegate(MTLRenderTargetType::kCAMetalLayer),
-      layer_(std::move(layer)) {
-  is_valid_ = layer_;
+    : IOSSurface(std::move(context)), layer_(std::move(layer)) {
+  if (!layer_) {
+    return;
+  }
+
   auto metal_context = CastToMetalContext(GetContext());
-  auto darwin_context = metal_context->GetDarwinContext().get();
-  command_queue_ = darwin_context.mtlCommandQueue;
-  device_ = darwin_context.mtlDevice;
+
+  layer_.get().device = metal_context->GetDevice().get();
+  layer_.get().presentsWithTransaction = YES;
+
+  is_valid_ = true;
 }
 
 // |IOSSurface|
@@ -42,60 +44,11 @@ void IOSSurfaceMetal::UpdateStorageSizeIfNecessary() {
 // |IOSSurface|
 std::unique_ptr<Surface> IOSSurfaceMetal::CreateGPUSurface(GrDirectContext* /* unused */) {
   auto metal_context = CastToMetalContext(GetContext());
-  return std::make_unique<GPUSurfaceMetal>(this,                            // layer
-                                           metal_context->GetMainContext()  // context
-  );
-}
-
-// |GPUSurfaceMetalDelegate|
-GPUCAMetalLayerHandle IOSSurfaceMetal::GetCAMetalLayer(const SkISize& frame_info) const {
-  CAMetalLayer* layer = layer_.get();
-  layer.device = device_;
-
-  layer.pixelFormat = MTLPixelFormatBGRA8Unorm;
-  // Flutter needs to read from the color attachment in cases where there are effects such as
-  // backdrop filters.
-  layer.framebufferOnly = NO;
-
-  const auto drawable_size = CGSizeMake(frame_info.width(), frame_info.height());
-  if (!CGSizeEqualToSize(drawable_size, layer.drawableSize)) {
-    layer.drawableSize = drawable_size;
-  }
-
-  // When there are platform views in the scene, the drawable needs to be presented in the same
-  // transaction as the one created for platform views. When the drawable are being presented from
-  // the raster thread, there is no such transaction.
-  layer.presentsWithTransaction = [[NSThread currentThread] isMainThread];
 
-  return layer;
-}
-
-// |GPUSurfaceMetalDelegate|
-bool IOSSurfaceMetal::PresentDrawable(GrMTLHandle drawable) const {
-  if (drawable == nullptr) {
-    FML_DLOG(ERROR) << "Could not acquire next Metal drawable from the SkSurface.";
-    return false;
-  }
-
-  auto command_buffer =
-      fml::scoped_nsprotocol<id<MTLCommandBuffer>>([[command_queue_ commandBuffer] retain]);
-  [command_buffer.get() commit];
-  [command_buffer.get() waitUntilScheduled];
-
-  [reinterpret_cast<id<CAMetalDrawable>>(drawable) present];
-  return true;
-}
-
-// |GPUSurfaceMetalDelegate|
-GPUMTLTextureInfo IOSSurfaceMetal::GetMTLTexture(const SkISize& frame_info) const {
-  FML_CHECK(false) << "render to texture not supported on ios";
-  return {.texture_id = -1, .texture = nullptr};
-}
-
-// |GPUSurfaceMetalDelegate|
-bool IOSSurfaceMetal::PresentTexture(intptr_t texture_id) const {
-  FML_CHECK(false) << "render to texture not supported on ios";
-  return false;
+  return std::make_unique<GPUSurfaceMetal>(layer_,                               // layer
+                                           metal_context->GetMainContext(),      // context
+                                           metal_context->GetMainCommandQueue()  // command queue
+  );
 }
 
 }  // namespace flutter

shell/platform/darwin/ios/rendering_api_selection.mm

@@ -6,17 +6,17 @@
 
 #include <Foundation/Foundation.h>
 #include <QuartzCore/CAEAGLLayer.h>
-#import <QuartzCore/CAMetalLayer.h>
-#if SHELL_ENABLE_METAL
+#include <QuartzCore/CAMetalLayer.h>
+#if FLUTTER_SHELL_ENABLE_METAL
 #include <Metal/Metal.h>
-#endif  // SHELL_ENABLE_METAL
+#endif  // FLUTTER_SHELL_ENABLE_METAL
 #import <TargetConditionals.h>
 
 #include "flutter/fml/logging.h"
 
 namespace flutter {
 
-#if SHELL_ENABLE_METAL
+#if FLUTTER_SHELL_ENABLE_METAL
 bool ShouldUseMetalRenderer() {
   bool ios_version_supports_metal = false;
   if (@available(iOS METAL_IOS_VERSION_BASELINE, *)) {
@@ -25,7 +25,7 @@ bool ShouldUseMetalRenderer() {
   }
   return ios_version_supports_metal;
 }
-#endif  // SHELL_ENABLE_METAL
+#endif  // FLUTTER_SHELL_ENABLE_METAL
 
 IOSRenderingAPI GetRenderingAPIForProcess(bool force_software) {
 #if TARGET_OS_SIMULATOR
@@ -39,12 +39,12 @@ IOSRenderingAPI GetRenderingAPIForProcess(bool force_software) {
   }
 #endif  // TARGET_OS_SIMULATOR
 
-#if SHELL_ENABLE_METAL
+#if FLUTTER_SHELL_ENABLE_METAL
   static bool should_use_metal = ShouldUseMetalRenderer();
   if (should_use_metal) {
     return IOSRenderingAPI::kMetal;
   }
-#endif  // SHELL_ENABLE_METAL
+#endif  // FLUTTER_SHELL_ENABLE_METAL
 
   // OpenGL will be emulated using software rendering by Apple on the simulator, so we use the
   // Skia software rendering since it performs a little better than the emulated OpenGL.