Derive the SourceAlpha filter input from SourceGraphic

Source/core/layout/svg/ReferenceFilterBuilder.cpp

 /*
  * Copyright (C) 2013 Adobe Systems Inc. All rights reserved.
  * Copyright (C) 2013 Google Inc.  All rights reserved.
  * Copyright (C) 2011 Apple Inc. 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 21 matching lines @@
 #include "core/css/CSSPrimitiveValue.h"
 #include "core/css/CSSPrimitiveValueMappings.h"
 #include "core/css/StylePropertySet.h"
 #include "core/dom/Element.h"
 #include "core/dom/ElementTraversal.h"
 #include "core/fetch/DocumentResource.h"
 #include "core/layout/svg/LayoutSVGResourceFilter.h"
 #include "core/svg/SVGDocumentExtensions.h"
 #include "core/svg/SVGFilterPrimitiveStandardAttributes.h"
 #include "core/svg/graphics/filters/SVGFilterBuilder.h"
-#include "platform/graphics/filters/SourceAlpha.h"
 
 namespace blink {
 
 HashMap<const FilterOperation*, OwnPtr<DocumentResourceReference>>* ReferenceFilterBuilder::documentResourceReferences = 0;
 
 DocumentResourceReference* ReferenceFilterBuilder::documentResourceReference(const FilterOperation* filterOperation)
 {
     if (!documentResourceReferences)
         return 0;
 
@@ skipping 82 matching lines @@
         // in the document.
         treeScope->document().accessSVGExtensions().addPendingResource(filterOperation->fragment(), toElement(layoutObject->node()));
         return nullptr;
     }
 
     if (!isSVGFilterElement(*filter))
         return nullptr;
 
     SVGFilterElement& filterElement = toSVGFilterElement(*filter);
 
-    // FIXME: Figure out what to do with SourceAlpha. Right now, we're
-    // using the alpha of the original input layer, which is obviously
-    // wrong. We should probably be extracting the alpha from the
-    // previousEffect, but this requires some more processing.
-    // This may need a spec clarification.
-    RefPtrWillBeRawPtr<SVGFilterBuilder> builder = SVGFilterBuilder::create(previousEffect, SourceAlpha::create(parentFilter));
+    RefPtrWillBeRawPtr<SVGFilterBuilder> builder = SVGFilterBuilder::create(previousEffect);
 
     ColorSpace filterColorSpace = ColorSpaceDeviceRGB;
     bool useFilterColorSpace = getSVGElementColorSpace(&filterElement, filterColorSpace);
 
     for (SVGElement* element = Traversal<SVGElement>::firstChild(filterElement); element; element = Traversal<SVGElement>::nextSibling(*element)) {
         if (!element->isFilterEffect())
             continue;
 
         SVGFilterPrimitiveStandardAttributes* effectElement = static_cast<SVGFilterPrimitiveStandardAttributes*>(element);
 
         RefPtrWillBeRawPtr<FilterEffect> effect = effectElement->build(builder.get(), parentFilter);
         if (!effect)
             continue;
 
         effectElement->setStandardAttributes(effect.get());
         effect->setEffectBoundaries(SVGLengthContext::resolveRectangle<SVGFilterPrimitiveStandardAttributes>(effectElement, filterElement.primitiveUnits()->currentValue()->enumValue(), parentFilter->sourceImageRect()));
         ColorSpace colorSpace = filterColorSpace;
         if (useFilterColorSpace || getSVGElementColorSpace(effectElement, colorSpace))
             effect->setOperatingColorSpace(colorSpace);
         builder->add(AtomicString(effectElement->result()->currentValue()->value()), effect);
     }
     return builder->lastEffect();
 }
 
 } // namespace blink