Derive the SourceAlpha filter input from SourceGraphic

Source/core/layout/svg/LayoutSVGResourceFilter.cpp

Index: Source/core/layout/svg/LayoutSVGResourceFilter.cpp
diff --git a/Source/core/layout/svg/LayoutSVGResourceFilter.cpp b/Source/core/layout/svg/LayoutSVGResourceFilter.cpp
index d9c412778cd4424fd3f959eaf1e77b6ecb2acfec..db677188d670e44d066b1a2f60492b42b1820ce7 100644
--- a/Source/core/layout/svg/LayoutSVGResourceFilter.cpp
+++ b/Source/core/layout/svg/LayoutSVGResourceFilter.cpp
@@ -27,7 +27,6 @@
 #include "core/dom/ElementTraversal.h"
 #include "core/svg/SVGFilterPrimitiveStandardAttributes.h"
 #include "platform/graphics/GraphicsContext.h"
-#include "platform/graphics/filters/SourceAlpha.h"
 #include "platform/graphics/filters/SourceGraphic.h"
 #include "third_party/skia/include/core/SkPicture.h"
 
@@ -99,7 +98,7 @@ PassRefPtrWillBeRawPtr<SVGFilterBuilder> LayoutSVGResourceFilter::buildPrimitive
     FloatRect targetBoundingBox = filter->targetBoundingBox();
 
     // Add effects to the builder
-    RefPtrWillBeRawPtr<SVGFilterBuilder> builder = SVGFilterBuilder::create(SourceGraphic::create(filter), SourceAlpha::create(filter));
+    RefPtrWillBeRawPtr<SVGFilterBuilder> builder = SVGFilterBuilder::create(SourceGraphic::create(filter));
     for (SVGElement* element = Traversal<SVGElement>::firstChild(*filterElement); element; element = Traversal<SVGElement>::nextSibling(*element)) {
         if (!element->isFilterEffect() || !element->layoutObject())
             continue;