Sky: Add a DrawLooper interface to the painting API to be used for shadows.

sky/engine/core/painting/Paint.cpp

Index: sky/engine/core/painting/Paint.cpp
diff --git a/sky/engine/core/painting/Paint.cpp b/sky/engine/core/painting/Paint.cpp
index f3e6fcae0fbd241cca373bde147ae83dce270c6c..a132a08252e57c6e2a5ef8cf9125bd0c58fbd6ff 100644
--- a/sky/engine/core/painting/Paint.cpp
+++ b/sky/engine/core/painting/Paint.cpp
@@ -5,6 +5,8 @@
 #include "sky/engine/config.h"
 #include "sky/engine/core/painting/Paint.h"
 
+#include "sky/engine/core/painting/DrawLooper.h"
+
 namespace blink {
 
 Paint::Paint()
@@ -15,4 +17,10 @@ Paint::~Paint()
 {
 }
 
+void Paint::setDrawLooper(DrawLooper* looper)
+{
+    ASSERT(looper);
+    m_paint.setLooper(looper->looper());
+}
+
 } // namespace blink