Allow ImageBitmaps derived from HTMLImageElements to be evicted from RAM.

Source/core/html/canvas/CanvasRenderingContext2D.cpp

 /*
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2010 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) 2007 Alp Toker <alp@atoker.com>
  * Copyright (C) 2008 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2008 Dirk Schulze <krit@webkit.org>
  * Copyright (C) 2010 Torch Mobile (Beijing) Co. Ltd. All rights reserved.
  * Copyright (C) 2012 Intel Corporation. All rights reserved.
  * Copyright (C) 2013 Adobe Systems Incorporated. All rights reserved.
  *
@@ skipping 1276 matching lines @@
 
     ASSERT(bitmap->height() && bitmap->width());
     FloatRect normalizedSrcRect = normalizeRect(srcRect);
     FloatRect normalizedDstRect = normalizeRect(dstRect);
 
     // Clip the rects to where the user thinks that the image is situated.
     clipRectsToImageRect(IntRect(IntPoint(), bitmap->size()), &normalizedSrcRect, &normalizedDstRect);
 
     FloatRect intersectRect = intersection(bitmapRect, normalizedSrcRect);
     FloatRect actualSrcRect(intersectRect);
-    actualSrcRect.move(-bitmapRect.x(), -bitmapRect.y());
 
-    FloatRect imageRect = FloatRect(FloatPoint(), bitmapRect.size());
+    IntPoint bitmapOffset = bitmap->bitmapOffset();
+    actualSrcRect.move(bitmapOffset - bitmapRect.location());
+    FloatRect imageRect = FloatRect(bitmapOffset, bitmapRect.size());
 
     FloatRect actualDstRect(FloatPoint(intersectRect.location() - normalizedSrcRect.location()), bitmapRect.size());
     actualDstRect.scale(normalizedDstRect.width() / normalizedSrcRect.width() * intersectRect.width() / bitmapRect.width(),
         normalizedDstRect.height() / normalizedSrcRect.height() * intersectRect.height() / bitmapRect.height());
     actualDstRect.moveBy(normalizedDstRect.location());
 
     if (!imageRect.intersects(actualSrcRect))
         return;
 
     RefPtr<Image> imageForRendering = bitmap->bitmapImage();
@@ skipping 1100 matching lines @@
     Color focusRingColor = RenderTheme::focusRingColor();
     const int focusRingWidth = 5;
     const int focusRingOutline = 0;
     c->drawFocusRing(path, focusRingWidth, focusRingOutline, focusRingColor);
     didDraw(path.boundingRect());
 
     c->restore();
 }
 
 } // namespace WebCore