Speed up SVG sprites by only painting the source rect in SVGImage::draw

Source/core/svg/graphics/SVGImage.cpp

 /*
  * Copyright (C) 2006 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2008, 2009 Apple Inc. All rights reserved.
  * Copyright (C) Research In Motion Limited 2011. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
@@ skipping 199 matching lines @@
     FloatPoint destOffset = dstRect.location() - topLeftOffset;
 
     context->translate(destOffset.x(), destOffset.y());
     context->scale(scale);
 
     view->resize(containerSize());
 
     if (view->needsLayout())
         view->layout();
 
-    view->paint(context, IntRect(0, 0, view->width(), view->height()));
+    view->paint(context, enclosingIntRect(srcRect));
 
     if (compositeOp != CompositeSourceOver)
         context->endTransparencyLayer();
 
     stateSaver.restore();
 
     if (imageObserver())
         imageObserver()->didDraw(this);
 }
 
@@ skipping 140 matching lines @@
 void SVGImage::reportMemoryUsage(MemoryObjectInfo* memoryObjectInfo) const
 {
     MemoryClassInfo info(memoryObjectInfo, this, WebCoreMemoryTypes::CachedResourceImage);
     Image::reportMemoryUsage(memoryObjectInfo);
     info.addMember(m_chromeClient, "chromeClient");
     info.addMember(m_page, "page");
 }
 
 }