Use an image generator to back SkPictureShader tiles.

src/core/SkPictureShader.h

Index: src/core/SkPictureShader.h
diff --git a/src/core/SkPictureShader.h b/src/core/SkPictureShader.h
index 8df9f539b8a77fb84d39c405035e2e095c38d3cb..3afe58f978bb174860f85ab751fb27217cfb6436 100644
--- a/src/core/SkPictureShader.h
+++ b/src/core/SkPictureShader.h
@@ -23,7 +23,6 @@ class SkPictureShader : public SkShader {
 public:
     static SkPictureShader* Create(const SkPicture*, TileMode, TileMode, const SkMatrix*,
                                    const SkRect*);
-    virtual ~SkPictureShader();
 
     size_t contextSize() const SK_OVERRIDE;
 
@@ -43,9 +42,9 @@ private:
 
     SkShader* refBitmapShader(const SkMatrix&, const SkMatrix* localMatrix) const;
 
-    const SkPicture* fPicture;
-    SkRect           fTile;
-    TileMode         fTmx, fTmy;
+    SkAutoTUnref<const SkPicture> fPicture;
+    SkRect                        fTile;
+    TileMode                      fTmx, fTmy;
 
     class PictureShaderContext : public SkShader::Context {
     public: