Merge tomhudson and mtklein SkPaint shrinking approaches.

src/core/SkPictureFlat.h

Index: src/core/SkPictureFlat.h
diff --git a/src/core/SkPictureFlat.h b/src/core/SkPictureFlat.h
index 6b4af13840e855ad8119de03a9534f4628d24cec..8e87e7185dde3e0355edb0c728de825f023537ea 100644
--- a/src/core/SkPictureFlat.h
+++ b/src/core/SkPictureFlat.h
@@ -561,15 +561,7 @@ private:
                    SkFlatData::Identity, SkFlatData::Hash, SkFlatData::Equal> fHash;
 };
 
-struct SkPaintTraits {
-    static void Flatten(SkWriteBuffer& buffer, const SkPaint& paint) {
-        paint.flatten(buffer);
-    }
-    static void Unflatten(SkReadBuffer& buffer, SkPaint* paint) {
-        paint->unflatten(buffer);
-    }
-};
-typedef SkFlatDictionary<SkPaint, SkPaintTraits> SkPaintDictionary;
+typedef SkFlatDictionary<SkPaint, SkPaint::FlatteningTraits> SkPaintDictionary;
 
 class SkChunkFlatController : public SkFlatController {
 public: