Extracting the SVG Filter Reference implementation out of the FilterEffectRenderer into its own typ…

Source/core/platform/graphics/filters/SkiaImageFilterBuilder.cpp

Index: Source/core/platform/graphics/filters/SkiaImageFilterBuilder.cpp
diff --git a/Source/core/platform/graphics/filters/SkiaImageFilterBuilder.cpp b/Source/core/platform/graphics/filters/SkiaImageFilterBuilder.cpp
index 50c3655ff3aefa010989e6bf9d41d0a3a7df4128..454bb0f30448be1e3ccfcdb633cbc391c4dfaa7d 100644
--- a/Source/core/platform/graphics/filters/SkiaImageFilterBuilder.cpp
+++ b/Source/core/platform/graphics/filters/SkiaImageFilterBuilder.cpp
@@ -33,6 +33,7 @@
 #include "core/platform/graphics/filters/DropShadowImageFilter.h"
 #include "core/platform/graphics/filters/FilterEffect.h"
 #include "core/platform/graphics/filters/FilterOperations.h"
+#include "core/platform/graphics/filters/SourceGraphic.h"
 
 namespace {
 
@@ -195,9 +196,16 @@ SkImageFilter* SkiaImageFilterBuilder::build(const FilterOperations& operations)
         const FilterOperation& op = *operations.at(i);
         switch (op.getOperationType()) {
         case FilterOperation::REFERENCE: {
-            FilterEffect* filterEffect = static_cast<const ReferenceFilterOperation*>(&op)->filterEffect();
-            // FIXME: hook up parent filter to image source
-            filter.reset(SkiaImageFilterBuilder::build(filterEffect));
+            const ReferenceFilterOperation* referenceFilterOperation = static_cast<const ReferenceFilterOperation*>(&op);
+            ReferenceFilter* referenceFilter = referenceFilterOperation->filter();
+            if (referenceFilter && referenceFilter->lastEffect()) {
+                // Link the source graphic to the previous filter in the chain.
+                m_map.set(referenceFilter->sourceGraphic(), filter);
+                filter.reset(SkiaImageFilterBuilder::build(referenceFilter->lastEffect()));
+                // We might have no reference to the SourceGraphic's Skia filter now, so make
+                // sure we don't keep it in the map anymore.
+                m_map.remove(referenceFilter->sourceGraphic());
+            }
             break;
         }
         case FilterOperation::GRAYSCALE: {