[WIP] Add Context to SkDrawLooper.

include/effects/SkLayerDrawLooper.h

Index: include/effects/SkLayerDrawLooper.h
diff --git a/include/effects/SkLayerDrawLooper.h b/include/effects/SkLayerDrawLooper.h
index 6955192b53f2e6f9edeb94f49efd0858a8a73b2b..edffee648660d6d89aa1224d0cfb87c44c445751 100644
--- a/include/effects/SkLayerDrawLooper.h
+++ b/include/effects/SkLayerDrawLooper.h
@@ -102,9 +102,8 @@ public:
     /// Similar to addLayer, but adds a layer to the top.
     SkPaint* addLayerOnTop(const LayerInfo&);
 
-    // overrides from SkDrawLooper
-    virtual void init(SkCanvas*);
-    virtual bool next(SkCanvas*, SkPaint* paint);
+    virtual SkDrawLooper::DrawContext* init(
+            SkCanvas*, void* storage, size_t storageSize) const SK_OVERRIDE;
 
     SK_DEVELOPER_TO_STRING()
     SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkLayerDrawLooper)
@@ -124,9 +123,18 @@ private:
     int     fCount;
 
     // state-machine during the init/next cycle
-    Rec* fCurrRec;
+    class LayerDrawLooperContext : public SkDrawLooper::DrawContext {
+    public:
+        explicit LayerDrawLooperContext(const SkLayerDrawLooper* looper);
+
+    protected:
+        virtual bool next(SkCanvas*, SkPaint* paint) SK_OVERRIDE;
 
-    static void ApplyInfo(SkPaint* dst, const SkPaint& src, const LayerInfo&);
+    private:
+        Rec* fCurrRec;
+
+        static void ApplyInfo(SkPaint* dst, const SkPaint& src, const LayerInfo&);
+    };
 
     class MyRegistrar : public SkFlattenable::Registrar {
     public: