Refactor AcceleratedStaticBitmapImage

third_party/WebKit/Source/platform/graphics/MailboxTextureHolder.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 MailboxTextureHolder_h
+#define MailboxTextureHolder_h
+
+#include "platform/PlatformExport.h"
+#include "platform/graphics/TextureHolder.h"
+#include "third_party/khronos/GLES2/gl2.h"
+#include "wtf/WeakPtr.h"
+
+namespace blink {
+
+class DrawingBuffer;

[Justin Novosad, 2016/11/08 14:33:27]

The dependency on DrawingBuffer here is quite yucky.  There's got to be a way to
make WeakPtrs on context providers or gl interface objects.  If that is too
inconvenient, you could wrap the context provider in an intermediate class that
exposes WeakPtr.

+
+class PLATFORM_EXPORT MailboxTextureHolder final : public TextureHolder {
+ public:
+  ~MailboxTextureHolder() override;
+
+  bool isSkiaTextureHolder() final { return false; }
+  bool isMailboxTextureHolder() final { return true; }
+  unsigned sharedContextId() final;
+  IntSize size() const final { return m_size; }
+  bool currentFrameKnownToBeOpaque(Image::MetadataMode) final { return false; }
+  WebThread* imageThread() final;
+
+  gpu::Mailbox mailbox() final { return m_mailbox; }
+  gpu::SyncToken syncToken() final { return m_syncToken; }
+  void updateSyncToken(gpu::SyncToken syncToken) final {
+    m_syncToken = syncToken;
+  }
+  void deleteTexture() final;
+
+  // In WebGL's commit or transferToImageBitmap calls, it will call the
+  // DrawingBuffer::transferToStaticBitmapImage function, which produces the
+  // input parameters for this method.
+  MailboxTextureHolder(const gpu::Mailbox&,
+                       const gpu::SyncToken&,
+                       unsigned textureIdToDeleteAfterMailboxConsumed,
+                       WeakPtr<DrawingBuffer>,
+                       IntSize mailboxSize);
+  // This function turns a texture-backed SkImage into a mailbox and a
+  // syncToken.
+  MailboxTextureHolder(std::unique_ptr<TextureHolder>);
+
+ private:
+  gpu::Mailbox m_mailbox;
+  gpu::SyncToken m_syncToken;
+  unsigned m_textureId;
+  WeakPtr<DrawingBuffer> m_drawingBuffer;

[Justin Novosad, 2016/11/08 14:33:27]

This should have a better name, to indicate that it provides access to the
context that owns m_textureId

+  IntSize m_size;
+  bool m_isConvertedFromSkiaTexture;
+};
+
+}  // namespace blink
+
+#endif  // MailboxTextureHolder_h