Reland of Allow canvases to be GPU-accelerated in Workers

third_party/WebKit/Source/platform/graphics/AcceleratedStaticBitmapImage.h

 // Copyright 2016 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 AcceleratedStaticBitmapImage_h
 #define AcceleratedStaticBitmapImage_h
 
+#include "base/threading/thread_checker.h"
 #include "gpu/command_buffer/common/mailbox.h"
 #include "gpu/command_buffer/common/sync_token.h"
 #include "platform/geometry/IntSize.h"
 #include "platform/graphics/StaticBitmapImage.h"
 #include "third_party/skia/include/core/SkRefCnt.h"
 
 #include <memory>
 
 class GrContext;
 
 namespace cc {
 class SingleReleaseCallback;
 }
 
 namespace blink {
+class WebThread;
 
 class PLATFORM_EXPORT AcceleratedStaticBitmapImage final : public StaticBitmapImage {
 public:
-    // SkImage with a texture backing that is assumed to be from the shared main thread context.
-    static PassRefPtr<AcceleratedStaticBitmapImage> create(sk_sp<SkImage>);
+    // SkImage with a texture backing that is assumed to be from the shared context of the current thread.
+    static PassRefPtr<AcceleratedStaticBitmapImage> createFromSharedContextImage(sk_sp<SkImage>);
     // Can specify the GrContext that created the texture backing the for the given SkImage. Ideally all callers would use this option.
     // The |mailbox| is a name for the texture backing the SkImage, allowing other contexts to use the same backing.
-    static PassRefPtr<AcceleratedStaticBitmapImage> create(sk_sp<SkImage>, sk_sp<GrContext>, const gpu::Mailbox&, const gpu::SyncToken&);
+    static PassRefPtr<AcceleratedStaticBitmapImage> createFromWebGLContextImage(sk_sp<SkImage>, const gpu::Mailbox&, const gpu::SyncToken&);
 
     ~AcceleratedStaticBitmapImage() override;
 
     // StaticBitmapImage overrides.
     sk_sp<SkImage> imageForCurrentFrame() override;
     void copyToTexture(WebGraphicsContext3DProvider*, GLuint destTextureId, GLenum destInternalFormat, GLenum destType, bool flipY) override;
 
+    // Image overrides.
+    void draw(SkCanvas*, const SkPaint&, const FloatRect& dstRect, const FloatRect& srcRect, RespectImageOrientationEnum, ImageClampingMode) override;
+
+    // To be called on sender thread before performing a transfer
+    void transfer() final;
+
 private:
     AcceleratedStaticBitmapImage(sk_sp<SkImage>);
-    AcceleratedStaticBitmapImage(sk_sp<SkImage>, sk_sp<GrContext>, const gpu::Mailbox&, const gpu::SyncToken&);
-
-    bool switchStorageToMailbox(WebGraphicsContext3DProvider*);
-    GLuint switchStorageToSkImageForWebGL(WebGraphicsContext3DProvider*);
-    GLuint switchStorageToSkImage(WebGraphicsContext3DProvider*);
+    AcceleratedStaticBitmapImage(sk_sp<SkImage>, const gpu::Mailbox&, const gpu::SyncToken&);
 
     void ensureMailbox();
+    void createImageFromMailboxIfNeeded();
+    void checkThread();
+    void waitSyncTokenIfNeeded();
+    bool isValid();
+    void releaseImageThreadSafe();
+    bool imageBelongsToSharedContext();
 
-    // True when the |m_image| has a texture id backing it from the shared main thread context.
-    bool m_imageIsForSharedMainThreadContext;
-
-    // Keeps the context alive that the SkImage is associated with. Not used if the SkImage is coming from the shared main
-    // thread context as we assume that context is kept alive elsewhere since it is globally shared in the process.
-    sk_sp<GrContext> m_grContext;
+    // Id of the shared context where m_image was created
+    unsigned m_sharedContextId;
     // True when the below mailbox and sync token are valid for getting at the texture backing the object's SkImage.
     bool m_hasMailbox = false;
     // A mailbox referring to the texture id backing the SkImage. The mailbox is valid as long as the SkImage is held alive.
     gpu::Mailbox m_mailbox;
     // This token must be waited for before using the mailbox.
     gpu::SyncToken m_syncToken;
+    // Thread that m_image belongs to. Set to null when m_image belong to the same thread
+    // as this AcceleratedStaticBitmapImage.  Should only be non-null after a transfer.
+    WebThread* m_imageThread = nullptr;
+
+    base::ThreadChecker m_threadChecker;
+    bool m_detachThreadAtNextCheck = false;
 };
 
 } // namespace blink
 
 #endif