Restore bitmap dedup in SkPictureRecord. Cuts RAM usage of DM by half.

src/core/SkPictureRecord.h

Index: src/core/SkPictureRecord.h
diff --git a/src/core/SkPictureRecord.h b/src/core/SkPictureRecord.h
index 6a577ca42ef19b59a0d3aa74b7ff49a35d12132f..8aee0a817a0a45f66163cab7f9a649ed5f22e48f 100644
--- a/src/core/SkPictureRecord.h
+++ b/src/core/SkPictureRecord.h
@@ -151,8 +151,7 @@ private:
         fWriter.writeScalar(scalar);
     }
 
-    // The command at 'offset' in the skp uses the specified bitmap
-    int addBitmap(const SkBitmap& bitmap);
+    void addBitmap(const SkBitmap& bitmap);
     void addMatrix(const SkMatrix& matrix);
     void addPaint(const SkPaint& paint) { this->addPaintPtr(&paint); }
     void addPaintPtr(const SkPaint* paint);