gpu/command_buffer/service/shared_image_representation.h - chromium/src - Git at Google

 // Copyright 2018 The Chromium 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 GPU_COMMAND_BUFFER_SERVICE_SHARED_IMAGE_REPRESENTATION_H_
 #define GPU_COMMAND_BUFFER_SERVICE_SHARED_IMAGE_REPRESENTATION_H_

 #include <dawn/dawn_proc_table.h>
 #include <dawn/webgpu.h>

 #include "base/callback_helpers.h"
 #include "base/util/type_safety/pass_key.h"
 #include "build/build_config.h"
 #include "components/viz/common/resources/resource_format.h"
 #include "gpu/command_buffer/service/shared_image_backing.h"
 #include "gpu/command_buffer/service/shared_image_manager.h"
 #include "gpu/gpu_gles2_export.h"
 #include "third_party/skia/include/core/SkSurface.h"
 #include "ui/gfx/color_space.h"
 #include "ui/gfx/geometry/rect.h"
 #include "ui/gfx/geometry/size.h"
 #include "ui/gfx/gpu_fence.h"

 typedef unsigned int GLenum;
 class SkPromiseImageTexture;

 namespace gl {
 class GLImage;
 }

 namespace gpu {
 class TextureBase;

 namespace gles2 {
 class Texture;
 class TexturePassthrough;
 }  // namespace gles2

 enum class RepresentationAccessMode {
   kNone,
   kRead,
   kWrite,
 };

 // A representation of a SharedImageBacking for use with a specific use case /
 // api.
 class GPU_GLES2_EXPORT SharedImageRepresentation {
  public:
   // Used by derived classes.
   enum class AllowUnclearedAccess { kYes, kNo };

   SharedImageRepresentation(SharedImageManager* manager,
                             SharedImageBacking* backing,
                             MemoryTypeTracker* tracker);
   virtual ~SharedImageRepresentation();

   viz::ResourceFormat format() const { return backing_->format(); }
   const gfx::Size& size() const { return backing_->size(); }
   const gfx::ColorSpace& color_space() const { return backing_->color_space(); }
   uint32_t usage() const { return backing_->usage(); }
   MemoryTypeTracker* tracker() { return tracker_; }
   bool IsCleared() const { return backing_->IsCleared(); }
   void SetCleared() { backing_->SetCleared(); }
   gfx::Rect ClearedRect() const { return backing_->ClearedRect(); }
   void SetClearedRect(const gfx::Rect& cleared_rect) {
     backing_->SetClearedRect(cleared_rect);
   }

   // Indicates that the underlying graphics context has been lost, and the
   // backing should be treated as destroyed.
   void OnContextLost() {
     has_context_ = false;
     backing_->OnContextLost();
   }

  protected:
   SharedImageManager* manager() const { return manager_; }
   SharedImageBacking* backing() const { return backing_; }
   bool has_context() const { return has_context_; }

   // Helper class for derived classes' Scoped*Access objects. Has tracking to
   // ensure a Scoped*Access does not outlive the representation it's associated
   // with.
   template <typename RepresentationClass>
   class ScopedAccessBase {
    public:
     ScopedAccessBase(RepresentationClass* representation)
         : representation_(representation) {
       DCHECK(!representation_->has_scoped_access_);
       representation_->has_scoped_access_ = true;
     }
     ~ScopedAccessBase() {
       DCHECK(representation_->has_scoped_access_);
       representation_->has_scoped_access_ = false;
     }

     RepresentationClass* representation() { return representation_; }

    private:
     RepresentationClass* const representation_;

     DISALLOW_COPY_AND_ASSIGN(ScopedAccessBase);
   };

  private:
   SharedImageManager* const manager_;
   SharedImageBacking* const backing_;
   MemoryTypeTracker* const tracker_;
   bool has_context_ = true;
   bool has_scoped_access_ = false;
 };

 class SharedImageRepresentationFactoryRef : public SharedImageRepresentation {
  public:
   SharedImageRepresentationFactoryRef(SharedImageManager* manager,
                                       SharedImageBacking* backing,
                                       MemoryTypeTracker* tracker)
       : SharedImageRepresentation(manager, backing, tracker) {}

   const Mailbox& mailbox() const { return backing()->mailbox(); }
   void Update(std::unique_ptr<gfx::GpuFence> in_fence) {
     backing()->Update(std::move(in_fence));
     backing()->OnWriteSucceeded();
   }
   bool ProduceLegacyMailbox(MailboxManager* mailbox_manager) {
     return backing()->ProduceLegacyMailbox(mailbox_manager);
   }
   bool PresentSwapChain() { return backing()->PresentSwapChain(); }
 };

 class GPU_GLES2_EXPORT SharedImageRepresentationGLTextureBase
     : public SharedImageRepresentation {
  public:
   class ScopedAccess
       : public ScopedAccessBase<SharedImageRepresentationGLTextureBase> {
    public:
     ScopedAccess(util::PassKey<SharedImageRepresentationGLTextureBase> pass_key,
                  SharedImageRepresentationGLTextureBase* representation)
         : ScopedAccessBase(representation) {}
     ~ScopedAccess() {
       representation()->UpdateClearedStateOnEndAccess();
       representation()->EndAccess();
     }
   };

   SharedImageRepresentationGLTextureBase(SharedImageManager* manager,
                                          SharedImageBacking* backing,
                                          MemoryTypeTracker* tracker)
       : SharedImageRepresentation(manager, backing, tracker) {}

   std::unique_ptr<ScopedAccess> BeginScopedAccess(
       GLenum mode,
       AllowUnclearedAccess allow_uncleared);

   virtual gpu::TextureBase* GetTextureBase() = 0;

  protected:
   friend class SharedImageRepresentationSkiaGL;

   // Can be overridden to handle clear state tracking when GL access begins or
   // ends.
   virtual void UpdateClearedStateOnBeginAccess() {}
   virtual void UpdateClearedStateOnEndAccess() {}

   // TODO(ericrk): Make these pure virtual and ensure real implementations
   // exist.
   virtual bool BeginAccess(GLenum mode);
   virtual void EndAccess() {}
 };

 class GPU_GLES2_EXPORT SharedImageRepresentationGLTexture
     : public SharedImageRepresentationGLTextureBase {
  public:
   SharedImageRepresentationGLTexture(SharedImageManager* manager,
                                      SharedImageBacking* backing,
                                      MemoryTypeTracker* tracker)
       : SharedImageRepresentationGLTextureBase(manager, backing, tracker) {}

   // TODO(ericrk): Move this to the ScopedAccess object. crbug.com/1003686
   virtual gles2::Texture* GetTexture() = 0;

   gpu::TextureBase* GetTextureBase() override;

  protected:
   void UpdateClearedStateOnBeginAccess() override;
   void UpdateClearedStateOnEndAccess() override;
 };

 class GPU_GLES2_EXPORT SharedImageRepresentationGLTexturePassthrough
     : public SharedImageRepresentationGLTextureBase {
  public:
   SharedImageRepresentationGLTexturePassthrough(SharedImageManager* manager,
                                                 SharedImageBacking* backing,
                                                 MemoryTypeTracker* tracker)
       : SharedImageRepresentationGLTextureBase(manager, backing, tracker) {}

   // TODO(ericrk): Move this to the ScopedAccess object. crbug.com/1003686
   virtual const scoped_refptr<gles2::TexturePassthrough>&
   GetTexturePassthrough() = 0;

   gpu::TextureBase* GetTextureBase() override;
 };

 class GPU_GLES2_EXPORT SharedImageRepresentationSkia
     : public SharedImageRepresentation {
  public:
   class GPU_GLES2_EXPORT ScopedWriteAccess
       : public ScopedAccessBase<SharedImageRepresentationSkia> {
    public:
     ScopedWriteAccess(util::PassKey<SharedImageRepresentationSkia> pass_key,
                       SharedImageRepresentationSkia* representation,
                       sk_sp<SkSurface> surface);
     ~ScopedWriteAccess();

     SkSurface* surface() const { return surface_.get(); }

    private:
     sk_sp<SkSurface> surface_;
   };

   class GPU_GLES2_EXPORT ScopedReadAccess
       : public ScopedAccessBase<SharedImageRepresentationSkia> {
    public:
     ScopedReadAccess(util::PassKey<SharedImageRepresentationSkia> pass_key,
                      SharedImageRepresentationSkia* representation,
                      sk_sp<SkPromiseImageTexture> promise_image_texture);
     ~ScopedReadAccess();

     SkPromiseImageTexture* promise_image_texture() const {
       return promise_image_texture_.get();
     }

    private:
     sk_sp<SkPromiseImageTexture> promise_image_texture_;
   };

   SharedImageRepresentationSkia(SharedImageManager* manager,
                                 SharedImageBacking* backing,
                                 MemoryTypeTracker* tracker)
       : SharedImageRepresentation(manager, backing, tracker) {}

   // Note: See BeginWriteAccess below for a description of the semaphore
   // parameters.
   std::unique_ptr<ScopedWriteAccess> BeginScopedWriteAccess(
       int final_msaa_count,
       const SkSurfaceProps& surface_props,
       std::vector<GrBackendSemaphore>* begin_semaphores,
       std::vector<GrBackendSemaphore>* end_semaphores,
       AllowUnclearedAccess allow_uncleared);

   std::unique_ptr<ScopedWriteAccess> BeginScopedWriteAccess(
       std::vector<GrBackendSemaphore>* begin_semaphores,
       std::vector<GrBackendSemaphore>* end_semaphores,
       AllowUnclearedAccess allow_uncleared);

   // Note: See BeginReadAccess below for a description of the semaphore
   // parameters.
   std::unique_ptr<ScopedReadAccess> BeginScopedReadAccess(
       std::vector<GrBackendSemaphore>* begin_semaphores,
       std::vector<GrBackendSemaphore>* end_semaphores);

   virtual bool SupportsMultipleConcurrentReadAccess();

  protected:
   // Begin the write access. The implementations should insert semaphores into
   // begin_semaphores vector which client will wait on before writing the
   // backing. The ownership of begin_semaphores will be passed to client.
   // The implementations should also insert semaphores into end_semaphores,
   // client must submit them with drawing operations which use the backing.
   // The ownership of end_semaphores are not passed to client. And client must
   // submit the end_semaphores before calling EndWriteAccess().
   virtual sk_sp<SkSurface> BeginWriteAccess(
       int final_msaa_count,
       const SkSurfaceProps& surface_props,
       std::vector<GrBackendSemaphore>* begin_semaphores,
       std::vector<GrBackendSemaphore>* end_semaphores) = 0;
   virtual void EndWriteAccess(sk_sp<SkSurface> surface) = 0;

   // Begin the read access. The implementations should insert semaphores into
   // begin_semaphores vector which client will wait on before reading the
   // backing. The ownership of begin_semaphores will be passed to client.
   // The implementations should also insert semaphores into end_semaphores,
   // client must submit them with drawing operations which use the backing.
   // The ownership of end_semaphores are not passed to client. And client must
   // submit the end_semaphores before calling EndReadAccess().
   virtual sk_sp<SkPromiseImageTexture> BeginReadAccess(
       std::vector<GrBackendSemaphore>* begin_semaphores,
       std::vector<GrBackendSemaphore>* end_semaphores) = 0;
   virtual void EndReadAccess() = 0;
 };

 class GPU_GLES2_EXPORT SharedImageRepresentationDawn
     : public SharedImageRepresentation {
  public:
   SharedImageRepresentationDawn(SharedImageManager* manager,
                                 SharedImageBacking* backing,
                                 MemoryTypeTracker* tracker)
       : SharedImageRepresentation(manager, backing, tracker) {}

   class GPU_GLES2_EXPORT ScopedAccess
       : public ScopedAccessBase<SharedImageRepresentationDawn> {
    public:
     ScopedAccess(util::PassKey<SharedImageRepresentationDawn> pass_key,
                  SharedImageRepresentationDawn* representation,
                  WGPUTexture texture);
     ~ScopedAccess();

     WGPUTexture texture() const { return texture_; }

    private:
     WGPUTexture texture_ = 0;
   };

   // Calls BeginAccess and returns a ScopedAccess object which will EndAccess
   // when it goes out of scope. The Representation must outlive the returned
   // ScopedAccess.
   std::unique_ptr<ScopedAccess> BeginScopedAccess(
       WGPUTextureUsage usage,
       AllowUnclearedAccess allow_uncleared);

  private:
   // This can return null in case of a Dawn validation error, for example if
   // usage is invalid.
   virtual WGPUTexture BeginAccess(WGPUTextureUsage usage) = 0;
   virtual void EndAccess() = 0;
 };

 class GPU_GLES2_EXPORT SharedImageRepresentationOverlay
     : public SharedImageRepresentation {
  public:
   SharedImageRepresentationOverlay(SharedImageManager* manager,
                                    SharedImageBacking* backing,
                                    MemoryTypeTracker* tracker)
       : SharedImageRepresentation(manager, backing, tracker) {}

   class ScopedReadAccess
       : public ScopedAccessBase<SharedImageRepresentationOverlay> {
    public:
     ScopedReadAccess(util::PassKey<SharedImageRepresentationOverlay> pass_key,
                      SharedImageRepresentationOverlay* representation,
                      gl::GLImage* gl_image);
     ~ScopedReadAccess() { representation()->EndReadAccess(); }

     gl::GLImage* gl_image() const {
       return gl_image_;
     }

    private:
     gl::GLImage* gl_image_;
   };

 #if defined(OS_ANDROID)
   virtual void NotifyOverlayPromotion(bool promotion,
                                       const gfx::Rect& bounds) = 0;
 #endif

   std::unique_ptr<ScopedReadAccess> BeginScopedReadAccess(bool needs_gl_image);

  protected:
   // TODO(weiliangc): Currently this only handles Android pre-SurfaceControl
   // case. Add appropriate fence later.
   virtual bool BeginReadAccess() = 0;
   virtual void EndReadAccess() = 0;

   // TODO(weiliangc): Add API to backing AHardwareBuffer.

   // TODO(penghuang): Refactor it to not depend on GL.
   // Get the backing as GLImage for GLSurface::ScheduleOverlayPlane.
   virtual gl::GLImage* GetGLImage() = 0;
 };

 }  // namespace gpu

 #endif  // GPU_COMMAND_BUFFER_SERVICE_SHARED_IMAGE_REPRESENTATION_H_
	// Copyright 2018 The Chromium 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 GPU_COMMAND_BUFFER_SERVICE_SHARED_IMAGE_REPRESENTATION_H_
	#define GPU_COMMAND_BUFFER_SERVICE_SHARED_IMAGE_REPRESENTATION_H_

	#include <dawn/dawn_proc_table.h>
	#include <dawn/webgpu.h>

	#include "base/callback_helpers.h"
	#include "base/util/type_safety/pass_key.h"
	#include "build/build_config.h"
	#include "components/viz/common/resources/resource_format.h"
	#include "gpu/command_buffer/service/shared_image_backing.h"
	#include "gpu/command_buffer/service/shared_image_manager.h"
	#include "gpu/gpu_gles2_export.h"
	#include "third_party/skia/include/core/SkSurface.h"
	#include "ui/gfx/color_space.h"
	#include "ui/gfx/geometry/rect.h"
	#include "ui/gfx/geometry/size.h"
	#include "ui/gfx/gpu_fence.h"

	typedef unsigned int GLenum;
	class SkPromiseImageTexture;

	namespace gl {
	class GLImage;
	}

	namespace gpu {
	class TextureBase;

	namespace gles2 {
	class Texture;
	class TexturePassthrough;
	} // namespace gles2

	enum class RepresentationAccessMode {
	kNone,
	kRead,
	kWrite,
	};

	// A representation of a SharedImageBacking for use with a specific use case /
	// api.
	class GPU_GLES2_EXPORT SharedImageRepresentation {
	public:
	// Used by derived classes.
	enum class AllowUnclearedAccess { kYes, kNo };

	SharedImageRepresentation(SharedImageManager* manager,
	SharedImageBacking* backing,
	MemoryTypeTracker* tracker);
	virtual ~SharedImageRepresentation();

	viz::ResourceFormat format() const { return backing_->format(); }
	const gfx::Size& size() const { return backing_->size(); }
	const gfx::ColorSpace& color_space() const { return backing_->color_space(); }
	uint32_t usage() const { return backing_->usage(); }
	MemoryTypeTracker* tracker() { return tracker_; }
	bool IsCleared() const { return backing_->IsCleared(); }
	void SetCleared() { backing_->SetCleared(); }
	gfx::Rect ClearedRect() const { return backing_->ClearedRect(); }
	void SetClearedRect(const gfx::Rect& cleared_rect) {
	backing_->SetClearedRect(cleared_rect);
	}

	// Indicates that the underlying graphics context has been lost, and the
	// backing should be treated as destroyed.
	void OnContextLost() {
	has_context_ = false;
	backing_->OnContextLost();
	}

	protected:
	SharedImageManager* manager() const { return manager_; }
	SharedImageBacking* backing() const { return backing_; }
	bool has_context() const { return has_context_; }

	// Helper class for derived classes' Scoped*Access objects. Has tracking to
	// ensure a Scoped*Access does not outlive the representation it's associated
	// with.
	template <typename RepresentationClass>
	class ScopedAccessBase {
	public:
	ScopedAccessBase(RepresentationClass* representation)
	: representation_(representation) {
	DCHECK(!representation_->has_scoped_access_);
	representation_->has_scoped_access_ = true;
	}
	~ScopedAccessBase() {
	DCHECK(representation_->has_scoped_access_);
	representation_->has_scoped_access_ = false;
	}

	RepresentationClass* representation() { return representation_; }

	private:
	RepresentationClass* const representation_;

	DISALLOW_COPY_AND_ASSIGN(ScopedAccessBase);
	};

	private:
	SharedImageManager* const manager_;
	SharedImageBacking* const backing_;
	MemoryTypeTracker* const tracker_;
	bool has_context_ = true;
	bool has_scoped_access_ = false;
	};

	class SharedImageRepresentationFactoryRef : public SharedImageRepresentation {
	public:
	SharedImageRepresentationFactoryRef(SharedImageManager* manager,
	SharedImageBacking* backing,
	MemoryTypeTracker* tracker)
	: SharedImageRepresentation(manager, backing, tracker) {}

	const Mailbox& mailbox() const { return backing()->mailbox(); }
	void Update(std::unique_ptr<gfx::GpuFence> in_fence) {
	backing()->Update(std::move(in_fence));
	backing()->OnWriteSucceeded();
	}
	bool ProduceLegacyMailbox(MailboxManager* mailbox_manager) {
	return backing()->ProduceLegacyMailbox(mailbox_manager);
	}
	bool PresentSwapChain() { return backing()->PresentSwapChain(); }
	};

	class GPU_GLES2_EXPORT SharedImageRepresentationGLTextureBase
	: public SharedImageRepresentation {
	public:
	class ScopedAccess
	: public ScopedAccessBase<SharedImageRepresentationGLTextureBase> {
	public:
	ScopedAccess(util::PassKey<SharedImageRepresentationGLTextureBase> pass_key,
	SharedImageRepresentationGLTextureBase* representation)
	: ScopedAccessBase(representation) {}
	~ScopedAccess() {
	representation()->UpdateClearedStateOnEndAccess();
	representation()->EndAccess();
	}
	};

	SharedImageRepresentationGLTextureBase(SharedImageManager* manager,
	SharedImageBacking* backing,
	MemoryTypeTracker* tracker)
	: SharedImageRepresentation(manager, backing, tracker) {}

	std::unique_ptr<ScopedAccess> BeginScopedAccess(
	GLenum mode,
	AllowUnclearedAccess allow_uncleared);

	virtual gpu::TextureBase* GetTextureBase() = 0;

	protected:
	friend class SharedImageRepresentationSkiaGL;

	// Can be overridden to handle clear state tracking when GL access begins or
	// ends.
	virtual void UpdateClearedStateOnBeginAccess() {}
	virtual void UpdateClearedStateOnEndAccess() {}

	// TODO(ericrk): Make these pure virtual and ensure real implementations
	// exist.
	virtual bool BeginAccess(GLenum mode);
	virtual void EndAccess() {}
	};

	class GPU_GLES2_EXPORT SharedImageRepresentationGLTexture
	: public SharedImageRepresentationGLTextureBase {
	public:
	SharedImageRepresentationGLTexture(SharedImageManager* manager,
	SharedImageBacking* backing,
	MemoryTypeTracker* tracker)
	: SharedImageRepresentationGLTextureBase(manager, backing, tracker) {}

	// TODO(ericrk): Move this to the ScopedAccess object. crbug.com/1003686
	virtual gles2::Texture* GetTexture() = 0;

	gpu::TextureBase* GetTextureBase() override;

	protected:
	void UpdateClearedStateOnBeginAccess() override;
	void UpdateClearedStateOnEndAccess() override;
	};

	class GPU_GLES2_EXPORT SharedImageRepresentationGLTexturePassthrough
	: public SharedImageRepresentationGLTextureBase {
	public:
	SharedImageRepresentationGLTexturePassthrough(SharedImageManager* manager,
	SharedImageBacking* backing,
	MemoryTypeTracker* tracker)
	: SharedImageRepresentationGLTextureBase(manager, backing, tracker) {}

	// TODO(ericrk): Move this to the ScopedAccess object. crbug.com/1003686
	virtual const scoped_refptr<gles2::TexturePassthrough>&
	GetTexturePassthrough() = 0;

	gpu::TextureBase* GetTextureBase() override;
	};

	class GPU_GLES2_EXPORT SharedImageRepresentationSkia
	: public SharedImageRepresentation {
	public:
	class GPU_GLES2_EXPORT ScopedWriteAccess
	: public ScopedAccessBase<SharedImageRepresentationSkia> {
	public:
	ScopedWriteAccess(util::PassKey<SharedImageRepresentationSkia> pass_key,
	SharedImageRepresentationSkia* representation,
	sk_sp<SkSurface> surface);
	~ScopedWriteAccess();

	SkSurface* surface() const { return surface_.get(); }

	private:
	sk_sp<SkSurface> surface_;
	};

	class GPU_GLES2_EXPORT ScopedReadAccess
	: public ScopedAccessBase<SharedImageRepresentationSkia> {
	public:
	ScopedReadAccess(util::PassKey<SharedImageRepresentationSkia> pass_key,
	SharedImageRepresentationSkia* representation,
	sk_sp<SkPromiseImageTexture> promise_image_texture);
	~ScopedReadAccess();

	SkPromiseImageTexture* promise_image_texture() const {
	return promise_image_texture_.get();
	}

	private:
	sk_sp<SkPromiseImageTexture> promise_image_texture_;
	};

	SharedImageRepresentationSkia(SharedImageManager* manager,
	SharedImageBacking* backing,
	MemoryTypeTracker* tracker)
	: SharedImageRepresentation(manager, backing, tracker) {}

	// Note: See BeginWriteAccess below for a description of the semaphore
	// parameters.
	std::unique_ptr<ScopedWriteAccess> BeginScopedWriteAccess(
	int final_msaa_count,
	const SkSurfaceProps& surface_props,
	std::vector<GrBackendSemaphore>* begin_semaphores,
	std::vector<GrBackendSemaphore>* end_semaphores,
	AllowUnclearedAccess allow_uncleared);

	std::unique_ptr<ScopedWriteAccess> BeginScopedWriteAccess(
	std::vector<GrBackendSemaphore>* begin_semaphores,
	std::vector<GrBackendSemaphore>* end_semaphores,
	AllowUnclearedAccess allow_uncleared);

	// Note: See BeginReadAccess below for a description of the semaphore
	// parameters.
	std::unique_ptr<ScopedReadAccess> BeginScopedReadAccess(
	std::vector<GrBackendSemaphore>* begin_semaphores,
	std::vector<GrBackendSemaphore>* end_semaphores);

	virtual bool SupportsMultipleConcurrentReadAccess();

	protected:
	// Begin the write access. The implementations should insert semaphores into
	// begin_semaphores vector which client will wait on before writing the
	// backing. The ownership of begin_semaphores will be passed to client.
	// The implementations should also insert semaphores into end_semaphores,
	// client must submit them with drawing operations which use the backing.
	// The ownership of end_semaphores are not passed to client. And client must
	// submit the end_semaphores before calling EndWriteAccess().
	virtual sk_sp<SkSurface> BeginWriteAccess(
	int final_msaa_count,
	const SkSurfaceProps& surface_props,
	std::vector<GrBackendSemaphore>* begin_semaphores,
	std::vector<GrBackendSemaphore>* end_semaphores) = 0;
	virtual void EndWriteAccess(sk_sp<SkSurface> surface) = 0;

	// Begin the read access. The implementations should insert semaphores into
	// begin_semaphores vector which client will wait on before reading the
	// backing. The ownership of begin_semaphores will be passed to client.
	// The implementations should also insert semaphores into end_semaphores,
	// client must submit them with drawing operations which use the backing.
	// The ownership of end_semaphores are not passed to client. And client must
	// submit the end_semaphores before calling EndReadAccess().
	virtual sk_sp<SkPromiseImageTexture> BeginReadAccess(
	std::vector<GrBackendSemaphore>* begin_semaphores,
	std::vector<GrBackendSemaphore>* end_semaphores) = 0;
	virtual void EndReadAccess() = 0;
	};

	class GPU_GLES2_EXPORT SharedImageRepresentationDawn
	: public SharedImageRepresentation {
	public:
	SharedImageRepresentationDawn(SharedImageManager* manager,
	SharedImageBacking* backing,
	MemoryTypeTracker* tracker)
	: SharedImageRepresentation(manager, backing, tracker) {}

	class GPU_GLES2_EXPORT ScopedAccess
	: public ScopedAccessBase<SharedImageRepresentationDawn> {
	public:
	ScopedAccess(util::PassKey<SharedImageRepresentationDawn> pass_key,
	SharedImageRepresentationDawn* representation,
	WGPUTexture texture);
	~ScopedAccess();

	WGPUTexture texture() const { return texture_; }

	private:
	WGPUTexture texture_ = 0;
	};

	// Calls BeginAccess and returns a ScopedAccess object which will EndAccess
	// when it goes out of scope. The Representation must outlive the returned
	// ScopedAccess.
	std::unique_ptr<ScopedAccess> BeginScopedAccess(
	WGPUTextureUsage usage,
	AllowUnclearedAccess allow_uncleared);

	private:
	// This can return null in case of a Dawn validation error, for example if
	// usage is invalid.
	virtual WGPUTexture BeginAccess(WGPUTextureUsage usage) = 0;
	virtual void EndAccess() = 0;
	};

	class GPU_GLES2_EXPORT SharedImageRepresentationOverlay
	: public SharedImageRepresentation {
	public:
	SharedImageRepresentationOverlay(SharedImageManager* manager,
	SharedImageBacking* backing,
	MemoryTypeTracker* tracker)
	: SharedImageRepresentation(manager, backing, tracker) {}

	class ScopedReadAccess
	: public ScopedAccessBase<SharedImageRepresentationOverlay> {
	public:
	ScopedReadAccess(util::PassKey<SharedImageRepresentationOverlay> pass_key,
	SharedImageRepresentationOverlay* representation,
	gl::GLImage* gl_image);
	~ScopedReadAccess() { representation()->EndReadAccess(); }

	gl::GLImage* gl_image() const {
	return gl_image_;
	}

	private:
	gl::GLImage* gl_image_;
	};

	#if defined(OS_ANDROID)
	virtual void NotifyOverlayPromotion(bool promotion,
	const gfx::Rect& bounds) = 0;
	#endif

	std::unique_ptr<ScopedReadAccess> BeginScopedReadAccess(bool needs_gl_image);

	protected:
	// TODO(weiliangc): Currently this only handles Android pre-SurfaceControl
	// case. Add appropriate fence later.
	virtual bool BeginReadAccess() = 0;
	virtual void EndReadAccess() = 0;

	// TODO(weiliangc): Add API to backing AHardwareBuffer.

	// TODO(penghuang): Refactor it to not depend on GL.
	// Get the backing as GLImage for GLSurface::ScheduleOverlayPlane.
	virtual gl::GLImage* GetGLImage() = 0;
	};

	} // namespace gpu

	#endif // GPU_COMMAND_BUFFER_SERVICE_SHARED_IMAGE_REPRESENTATION_H_