Refactor AcceleratedStaticBitmapImage

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

 // Copyright 2014 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 StaticBitmapImage_h
 #define StaticBitmapImage_h
 
 #include "gpu/command_buffer/common/mailbox.h"
 #include "gpu/command_buffer/common/sync_token.h"
 #include "platform/graphics/Image.h"
@@ skipping 20 matching lines @@
             const FloatRect& srcRect,
             RespectImageOrientationEnum,
             ImageClampingMode) override;
 
   sk_sp<SkImage> imageForCurrentFrame() override;
 
   bool originClean() const { return m_isOriginClean; }
   void setOriginClean(bool flag) { m_isOriginClean = flag; }
   bool isPremultiplied() const { return m_isPremultiplied; }
   void setPremultiplied(bool flag) { m_isPremultiplied = flag; }
+  // In our current design, the SkImage in this class is always *not*
+  // texture-backed.
   bool isTextureBacked() override;
   virtual void copyToTexture(WebGraphicsContext3DProvider*,
                              GLuint,
                              GLenum,
                              GLenum,
                              bool) {
     NOTREACHED();
   }
   virtual bool hasMailbox() { return false; }
   virtual void transfer() {}
 
+  virtual void ensureMailbox() {}
   virtual gpu::Mailbox getMailbox() { return gpu::Mailbox(); }
   virtual gpu::SyncToken getSyncToken() { return gpu::SyncToken(); }
-  virtual void ensureMailbox() {}
+  virtual void updateSyncToken(gpu::SyncToken) {}
 
  protected:
-  StaticBitmapImage(sk_sp<SkImage>);
   StaticBitmapImage();  // empty constructor for derived class.
   sk_sp<SkImage> m_image;

[Justin Novosad, 2016/10/28 21:58:41]

I find it clumsy that AcceleratedStaticBitmapImage ends up with two SkImage
references.  I thinking we should get rid of this one, and create a new subclass
(UnacceleratedStaticBitmapImage) that basically just has m_image, and implements
imageForCurrentFrame().  By removing the implementation of imageForCurrentFrame
from StaticBitmapImage, this class will become abstract.

 
  private:
+  StaticBitmapImage(sk_sp<SkImage>);
   bool m_isOriginClean = true;
   // The premultiply info is stored here because the SkImage API
   // doesn't expose this info.
   bool m_isPremultiplied = true;
 };
 
 }  // namespace blink
 
 #endif