Refactor AcceleratedStaticBitmapImage

third_party/WebKit/Source/platform/graphics/TextureHolder.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 TextureHolder_h
+#define TextureHolder_h
+
+#include "gpu/command_buffer/common/mailbox.h"
+#include "gpu/command_buffer/common/sync_token.h"
+#include "platform/PlatformExport.h"
+#include "platform/WebTaskRunner.h"
+#include "platform/geometry/IntSize.h"
+#include "platform/graphics/Image.h"
+#include "third_party/skia/include/core/SkImage.h"
+#include "third_party/skia/include/core/SkRefCnt.h"
+
+namespace blink {
+
+class WebThread;
+
+class PLATFORM_EXPORT TextureHolder {
+ public:
+  virtual ~TextureHolder() {}
+
+  // Methods overrided by all sub-classes
+  virtual bool isSkiaTextureHolder() = 0;
+  virtual bool isMailboxTextureHolder() = 0;
+  virtual unsigned sharedContextId() = 0;
+  virtual IntSize size() const = 0;
+  virtual bool currentFrameKnownToBeOpaque(Image::MetadataMode) = 0;
+
+  // Methods overrided by MailboxTextureHolder
+  virtual gpu::Mailbox mailbox() {
+    NOTREACHED();
+    return gpu::Mailbox();
+  }
+  virtual gpu::SyncToken syncToken() {
+    NOTREACHED();
+    return gpu::SyncToken();
+  }
+  virtual void updateSyncToken(gpu::SyncToken) { NOTREACHED(); }
+
+  // Methods overrided by SkiaTextureHolder
+  virtual sk_sp<SkImage> skImage() {
+    NOTREACHED();
+    return nullptr;
+  }
+  virtual void setSharedContextId(unsigned) { NOTREACHED(); }
+  virtual void setImageThread(WebThread*) { NOTREACHED(); }
+  virtual void setImageThreadTaskRunner(std::unique_ptr<WebTaskRunner>) {
+    NOTREACHED();
+  }
+
+  // Methods that have exactly the same impelmentation for all sub-classes
+  WebThread* textureThread() { return m_textureThreadDoNotCall; }

[Justin Novosad, 2016/11/08 19:38:54]

This is never called, but it should be. make the data member private instead of
protected.

[xidachen, 2016/11/08 20:30:58]

Done.

+  void setTextureThread(WebThread* thread) {
+    m_textureThreadDoNotCall = thread;

[Justin Novosad, 2016/11/08 19:38:54]

The only thing we ever do with this value, as far as I can tell, is verify
whether it is NULL.  IMHO, you should replace it with a bool m_wasTranferred.

[xidachen, 2016/11/08 20:30:58]

Done.

+  }
+  void setTextureThreadTaskRunner(std::unique_ptr<WebTaskRunner> taskRunner) {
+    m_textureThreadTaskRunner = std::move(taskRunner);
+  }
+
+ protected:
+  // Thread that |m_texture| in the AcceleratedStaticBitmapImage belongs to. Set
+  // to null when |m_texture| 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_textureThreadDoNotCall = nullptr;
+  // Keep a clone of the WebTaskRunner for m_textureThread. This is to handle
+  // the case where |m_textureThread| goes out of scope, and we still need to
+  // use
+  // the WebTaskRunner for the |m_textureThread|.
+  std::unique_ptr<WebTaskRunner> m_textureThreadTaskRunner;
+};
+
+}  // namespace blink
+
+#endif  // TextureHolder_h