Fixes the rendering of a SVG filter (e.g. feFlood) by testing against total

Source/core/rendering/svg/RenderSVGResourceFilter.cpp

 /*
  * Copyright (C) 2004, 2005, 2006, 2007 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) 2004, 2005 Rob Buis <buis@kde.org>
  * Copyright (C) 2005 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2009 Dirk Schulze <krit@webkit.org>
  * Copyright (C) Research In Motion Limited 2010. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
@@ skipping 91 matching lines @@
         effect->setEffectBoundaries(SVGLengthContext::resolveRectangle<SVGFilterPrimitiveStandardAttributes>(effectElement, filterElement->primitiveUnits()->currentValue()->enumValue(), targetBoundingBox));
         effect->setOperatingColorSpace(
             effectElement->renderer()->style()->svgStyle()->colorInterpolationFilters() == CI_LINEARRGB ? ColorSpaceLinearRGB : ColorSpaceDeviceRGB);
         builder->add(AtomicString(effectElement->result()->currentValue()->value()), effect);
     }
     return builder.release();
 }
 
 bool RenderSVGResourceFilter::fitsInMaximumImageSize(const FloatSize& size, FloatSize& scale)
 {
-    bool matchesFilterSize = true;
-    if (size.width() * scale.width() > kMaxFilterSize) {
-        scale.setWidth(kMaxFilterSize / size.width());
-        matchesFilterSize = false;
-    }
-    if (size.height() * scale.height() > kMaxFilterSize) {
-        scale.setHeight(kMaxFilterSize / size.height());
-        matchesFilterSize = false;
-    }
+    FloatSize scaledSize(size);
+    scaledSize.scale(scale.width(), scale.height());
+    float scaledArea = scaledSize.width() * scaledSize.height();
 
-    return matchesFilterSize;
+    if (scaledArea <= FilterEffect::maxFilterArea())
+        return true;
+
+    // If area of scaled size is bigger than the upper limit, adjust the scale
+    // to fit.
+    scale.scale(sqrt(FilterEffect::maxFilterArea() / scaledArea));
+    return false;
 }
 
 static bool createImageBuffer(const Filter* filter, OwnPtr<ImageBuffer>& imageBuffer, bool accelerated)
 {
     IntRect paintRect = filter->sourceImageRect();
     // Don't create empty ImageBuffers.
     if (paintRect.isEmpty())
         return false;
 
     OwnPtr<ImageBufferSurface> surface;
@@ skipping 276 matching lines @@
     markAllClientLayersForInvalidation();
 }
 
 FloatRect RenderSVGResourceFilter::drawingRegion(RenderObject* object) const
 {
     FilterData* filterData = m_filter.get(object);
     return filterData ? filterData->drawingRegion : FloatRect();
 }
 
 }