Implement SVG masking with slimming paint

Source/core/paint/CompositingRecorder.h

Index: Source/core/paint/CompositingRecorder.h
diff --git a/Source/core/paint/CompositingRecorder.h b/Source/core/paint/CompositingRecorder.h
index 99eb5fb8abef90b88cd34a546d0428b2bcb92d6e..852dc94c4c0b471aa650bdeae43080fdc378c5b5 100644
--- a/Source/core/paint/CompositingRecorder.h
+++ b/Source/core/paint/CompositingRecorder.h
@@ -5,6 +5,7 @@
 #ifndef CompositingRecorder_h
 #define CompositingRecorder_h
 
+#include "platform/geometry/FloatRect.h"
 #include "platform/graphics/GraphicsTypes.h"
 #include "platform/graphics/paint/DisplayItem.h"
 #include "public/platform/WebBlendMode.h"
@@ -16,7 +17,7 @@ class LayoutObject;
 
 class CompositingRecorder {
 public:
-    explicit CompositingRecorder(GraphicsContext*, DisplayItemClient, const CompositeOperator, const WebBlendMode&, const float);
+    explicit CompositingRecorder(GraphicsContext*, DisplayItemClient, const SkXfermode::Mode, const float, const FloatRect* = 0, ColorFilter = ColorFilterNone);
 
     ~CompositingRecorder();