[WIP] Add Context to SkDrawLooper.

include/effects/SkLayerDrawLooper.h

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkLayerDrawLooper_DEFINED
 #define SkLayerDrawLooper_DEFINED
 
@@ skipping 85 matching lines @@
 
     /**
      *  This layer will with the original paint and no offset.
      */
     void addLayer() { this->addLayer(0, 0); }
 
     /// 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*) const;
 
     SK_DEVELOPER_TO_STRING()
     SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkLayerDrawLooper)
 
 protected:
     SkLayerDrawLooper(SkReadBuffer&);
     virtual void flatten(SkWriteBuffer&) const SK_OVERRIDE;
 
+    virtual bool next_internal(SkCanvas*, SkPaint* paint,
+                               SkDrawLooper::DrawContext* context) const;
+
 private:
     struct Rec {
         Rec*    fNext;
         SkPaint fPaint;
         LayerInfo fInfo;
     };
     Rec*    fRecs;
     Rec*    fTopRec;
     int     fCount;
 
     // state-machine during the init/next cycle
-    Rec* fCurrRec;
+    struct SkLayerDrawLooperContext : public SkDrawLooper::DrawContext {
+        explicit SkLayerDrawLooperContext(const SkLayerDrawLooper* looper);
+        Rec* fCurrRec;
+    };
 
     static void ApplyInfo(SkPaint* dst, const SkPaint& src, const LayerInfo&);
 
     class MyRegistrar : public SkFlattenable::Registrar {
     public:
         MyRegistrar();
     };
 
     typedef SkDrawLooper INHERITED;
 };
 
 #endif