Derive the SourceAlpha filter input from SourceGraphic

Source/platform/graphics/filters/SourceAlpha.cpp

 /*
  * Copyright (C) 2009 Dirk Schulze <krit@webkit.org>
  * Copyright (C) 2013 Google Inc. 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
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Library General Public License for more details.
  *
  * You should have received a copy of the GNU Library General Public License
  * along with this library; see the file COPYING.LIB.  If not, write to
  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  */
 
 #include "config.h"
 #include "platform/graphics/filters/SourceAlpha.h"
 
-#include "platform/graphics/Color.h"
 #include "platform/graphics/filters/Filter.h"
 #include "platform/graphics/filters/SkiaImageFilterBuilder.h"
-#include "platform/graphics/filters/SourceGraphic.h"
 #include "platform/text/TextStream.h"
 #include "third_party/skia/include/effects/SkColorFilterImageFilter.h"
 #include "third_party/skia/include/effects/SkColorMatrixFilter.h"
 #include "wtf/text/WTFString.h"
 
 namespace blink {
 
-PassRefPtrWillBeRawPtr<SourceAlpha> SourceAlpha::create(Filter* filter)
+PassRefPtrWillBeRawPtr<SourceAlpha> SourceAlpha::create(FilterEffect* sourceEffect)
 {
-    return adoptRefWillBeNoop(new SourceAlpha(filter));
+    return adoptRefWillBeNoop(new SourceAlpha(sourceEffect));
 }
 
 const AtomicString& SourceAlpha::effectName()
 {
     DEFINE_STATIC_LOCAL(const AtomicString, s_effectName, ("SourceAlpha", AtomicString::ConstructFromLiteral));
     return s_effectName;
 }
 
+SourceAlpha::SourceAlpha(FilterEffect* sourceEffect)
+    : FilterEffect(sourceEffect->filter())
+{
+    setOperatingColorSpace(sourceEffect->operatingColorSpace());
+    inputEffects().append(sourceEffect);
+}
+
 FloatRect SourceAlpha::determineAbsolutePaintRect(const FloatRect& requestedRect)
 {
-    FloatRect srcRect = filter()->sourceImageRect();
-    srcRect.intersect(requestedRect);
-    addAbsolutePaintRect(srcRect);
-    return srcRect;
+    return inputEffect(0)->determineAbsolutePaintRect(requestedRect);
 }
 
 PassRefPtr<SkImageFilter> SourceAlpha::createImageFilter(SkiaImageFilterBuilder* builder)
 {
-    RefPtr<SkImageFilter> sourceGraphic(builder->build(builder->sourceGraphic(), operatingColorSpace()));
+    RefPtr<SkImageFilter> sourceGraphic(builder->build(inputEffect(0), operatingColorSpace()));
     SkScalar matrix[20] = {
         0, 0, 0, 0, 0,
         0, 0, 0, 0, 0,
         0, 0, 0, 0, 0,
         0, 0, 0, SK_Scalar1, 0
     };
     RefPtr<SkColorFilter> colorFilter(adoptRef(SkColorMatrixFilter::Create(matrix)));
     return adoptRef(SkColorFilterImageFilter::Create(colorFilter.get(), sourceGraphic.get()));
 }
 
 TextStream& SourceAlpha::externalRepresentation(TextStream& ts, int indent) const
 {
     writeIndent(ts, indent);
     ts << "[SourceAlpha]\n";
     return ts;
 }
 
 } // namespace blink