Make ImageBitmap Transferable

third_party/WebKit/Source/core/frame/ImageBitmap.cpp

 // Copyright 2013 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.
 
 #include "config.h"
 #include "core/frame/ImageBitmap.h"
 
 #include "core/html/HTMLCanvasElement.h"
 #include "core/html/HTMLVideoElement.h"
 #include "core/html/ImageData.h"
@@ skipping 163 matching lines @@
     IntRect normalizedCropRect = normalizeRect(cropRect);
     return adoptRefWillBeNoop(new ImageBitmap(bitmap, normalizedCropRect));
 }
 
 PassRefPtrWillBeRawPtr<ImageBitmap> ImageBitmap::create(Image* image, const IntRect& cropRect)
 {
     IntRect normalizedCropRect = normalizeRect(cropRect);
     return adoptRefWillBeNoop(new ImageBitmap(image, normalizedCropRect));
 }
 
+PassRefPtrWillBeRawPtr<ImageBitmap> ImageBitmap::transfer()
+{
+    WTF::RawPtr<ImageBitmap> bitmap = adoptRefWillBeNoop(new ImageBitmap(this, m_cropRect));

[haraken, 2015/10/26 14:57:40]

RefPtrWillBeRawPtr

[xidachen, 2015/10/27 12:23:24]

Done.

+    if (m_imageElement)
+        m_imageElement.clear();
+    if (m_bitmap)
+        m_bitmap.clear();
+    return bitmap;

[haraken, 2015/10/26 14:57:40]

bitmap.release()

[xidachen, 2015/10/27 12:23:24]

junov@: I had to add back the code that sets the m_bitmapRect to be 0. The
reason is this: there is a V8ImageBitmap reference pointer that points to this
ImageBitmap object, so even though the m_bitmap is cleared, the V8ImageBitmap
pointer can still see the size of this ImageBitmap object. Actually by looking
back at this CL, I found out that the "expected.txt" is wrong starting from
Patch Set #4, which is because I didn't explicitly set the m_bitmapRect to be 0.
Now that I put it back, the "expected.txt" is correct.

[xidachen, 2015/10/27 12:23:24]

Done.

+}
+
 void ImageBitmap::notifyImageSourceChanged()
 {
     m_bitmap = cropImage(m_imageElement->cachedImage()->image(), m_cropRect);
     m_bitmapOffset = IntPoint();
     m_imageElement = nullptr;
 }
 
 PassRefPtr<Image> ImageBitmap::bitmapImage() const
 {
     ASSERT((m_imageElement || m_bitmap || !m_bitmapRect.width() || !m_bitmapRect.height()) && (!m_imageElement || !m_bitmap));
@@ skipping 26 matching lines @@
     return FloatSize(width(), height());
 }
 
 DEFINE_TRACE(ImageBitmap)
 {
     visitor->trace(m_imageElement);
     ImageLoaderClient::trace(visitor);
 }
 
 } // namespace blink