Trace picture piles on layers

cc/debug/traced_picture.cc

Index: cc/debug/traced_picture.cc
diff --git a/cc/debug/traced_picture.cc b/cc/debug/traced_picture.cc
index 756470a7764b89d3bff3e47b51b335a9b7fc8daf..33ae7e1daf5971982e1a9411f7fc8605ef8fa47c 100644
--- a/cc/debug/traced_picture.cc
+++ b/cc/debug/traced_picture.cc
@@ -28,9 +28,16 @@ scoped_ptr<base::debug::ConvertableToTraceFormat>
 void TracedPicture::AppendAsTraceFormat(std::string* out) const {
   std::string encoded_picture;
   picture_->AsBase64String(&encoded_picture);
-  out->append("\"");
+  out->append("{");
+  out->append("\"layer_rect\": [");
+  base::StringAppendF(
+      out, "%i,%i,%i,%i",
+      picture_->LayerRect().x(), picture_->LayerRect().y(),
+      picture_->LayerRect().width(), picture_->LayerRect().height());
+  out->append("],");
+  out->append("\"data_b64\": \"");
   out->append(encoded_picture);
-  out->append("\"");
+  out->append("\"}");
 }
 
 }  // namespace cc