Refactor AcceleratedStaticBitmapImage

third_party/WebKit/Source/platform/graphics/SkiaTextureHolder.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 SkiaTextureHolder_h
+#define SkiaTextureHolder_h
+
+#include "platform/PlatformExport.h"
+#include "platform/graphics/TextureHolder.h"
+
+namespace blink {
+
+class PLATFORM_EXPORT SkiaTextureHolder final : public TextureHolder {
+ public:
+  ~SkiaTextureHolder() override;
+
+  bool isSkiaTextureHolder() final { return true; }
+  bool isMailboxTextureHolder() final { return false; }
+  unsigned sharedContextId() final;
+  IntSize size() const final {
+    return IntSize(m_image->width(), m_image->height());
+  }
+  bool currentFrameKnownToBeOpaque(Image::MetadataMode) final {
+    return m_image->isOpaque();
+  }
+  WebThread* imageThread() final { return m_imageThreadDoNotCall; }
+
+  sk_sp<SkImage> skImage() final { return m_image; }
+  void setSharedContextId(unsigned contextId) final {
+    m_sharedContextId = contextId;
+  }
+  void setImageThread(WebThread* thread) { m_imageThreadDoNotCall = thread; }
+  void setImageThreadTaskRunner(
+      std::unique_ptr<WebTaskRunner> taskRunner) final {
+    m_imageThreadTaskRunner = std::move(taskRunner);
+  }
+
+  // When creating a AcceleratedStaticBitmap from a texture-backed SkImage, this
+  // function will be called to create a TextureHolder object.
+  SkiaTextureHolder(sk_sp<SkImage>);
+  // This function consumes the mailbox in the input parameter and turn it into
+  // a texture-backed SkImage.
+  SkiaTextureHolder(std::unique_ptr<TextureHolder>);
+
+ private:
+  void releaseImageThreadSafe();
+
+  // The m_image should always be texture-backed
+  sk_sp<SkImage> m_image;
+  // Id of the shared context where m_image was created
+  unsigned m_sharedContextId = 0;
+  // Thread that |m_image| belongs to. Set to null when |m_image| belongs to the
+  // same thread as the AcceleratedStaticBitmapImage.  Should only be non-null
+  // after a transfer.
+  // VERY IMPORTANT: Used for pointer comparisons only. DO NOT call any of its
+  // API because that would potentially CRASH.
+  WebThread* m_imageThreadDoNotCall;
+  // Keep a clone of the WebTaskRunner for m_imageThread. This is to handle
+  // the case where |m_imageThread| goes out of scope, and we still need to use
+  // the WebTaskRunner for the |m_imageThread|.
+  std::unique_ptr<WebTaskRunner> m_imageThreadTaskRunner;
+};
+
+}  // namespace blink
+
+#endif  // SkiaTextureHolder_h