Merge two determineFilterPrimitiveSubregion implementations

Source/core/rendering/FilterEffectRenderer.cpp

 /*
  * Copyright (C) 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2013 Google 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.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 355 matching lines @@
     // Get the zoom factor to scale the filterSourceRect input
     const RenderLayerModelObject* renderer = renderLayer->renderer();
     const RenderStyle* style = renderer ? renderer->style() : 0;
     float zoom = style ? style->effectiveZoom() : 1.0f;
 
     AffineTransform absoluteTransform;
     absoluteTransform.translate(filterBoxRect.x(), filterBoxRect.y());
     filter->setAbsoluteTransform(absoluteTransform);
     filter->setAbsoluteFilterRegion(AffineTransform().scale(zoom).mapRect(filterSourceRect));
     filter->setFilterRegion(absoluteTransform.inverse().mapRect(filterSourceRect));
-    filter->lastEffect()->determineFilterPrimitiveSubregion();
+    filter->lastEffect()->determineFilterPrimitiveSubregion(MapRectForward);
 
     bool hasUpdatedBackingStore = filter->updateBackingStoreRect(filterSourceRect);
     if (filter->hasFilterThatMovesPixels()) {
         if (hasUpdatedBackingStore)
             m_repaintRect = filterSourceRect;
         else {
             m_repaintRect.unite(layerRepaintRect);
             m_repaintRect.intersect(filterSourceRect);
         }
     }
@@ skipping 39 matching lines @@
     // Get the filtered output and draw it in place.
     m_savedGraphicsContext->drawImageBuffer(filter->output(), filter->outputRect(), CompositeSourceOver);
 
     filter->clearIntermediateResults();
 
     return m_savedGraphicsContext;
 }
 
 } // namespace WebCore