Refactoring source image usage in CanvasRenderingContext2D

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 182 matching lines @@
 }
 
 PassRefPtr<Image> ImageBitmap::bitmapImage() const
 {
     ASSERT((m_imageElement || m_bitmap || !m_bitmapRect.width() || !m_bitmapRect.height()) && (!m_imageElement || !m_bitmap));
     if (m_imageElement)
         return m_imageElement->cachedImage()->image();
     return m_bitmap;
 }
 
+PassRefPtr<Image> ImageBitmap::getSourceImageForCanvas(HTMLCanvasElement*, ExceptionState&, CanvasImageSourceUsage usage, bool* isVolatile) const
+{
+    if (isVolatile)
+        *isVolatile = false;
+    return bitmapImage();
 }
+
+void ImageBitmap::adjustDrawRects(FloatRect* srcRect, FloatRect* dstRect) const
+{
+    FloatRect intersectRect = intersection(m_bitmapRect, *srcRect);
+    FloatRect newSrcRect = intersectRect;
+    newSrcRect.move(m_bitmapOffset - m_bitmapRect.location());
+    FloatRect newDstRect(FloatPoint(intersectRect.location() - srcRect->location()), m_bitmapRect.size());
+    newDstRect.scale(dstRect->width() / srcRect->width() * intersectRect.width() / m_bitmapRect.width(),
+        dstRect->height() / srcRect->height() * intersectRect.height() / m_bitmapRect.height());
+    newDstRect.moveBy(dstRect->location());
+    *srcRect = newSrcRect;
+    *dstRect = newDstRect;
+}
+
+FloatSize ImageBitmap::sourceSize() const
+{
+    return FloatSize(width(), height());
+}
+
+}