Make reftests work for sky.

sky/viewer/document_view.cc

Index: sky/viewer/document_view.cc
diff --git a/sky/viewer/document_view.cc b/sky/viewer/document_view.cc
index 51eae14a4c3aa48952c152ec157ee0c27f8d7678..722a935ebe915a0fe9b56cf0a6e8cd72641ef39e 100644
--- a/sky/viewer/document_view.cc
+++ b/sky/viewer/document_view.cc
@@ -80,8 +80,8 @@ DocumentView::DocumentView(
       root_(NULL),
       view_manager_client_factory_(shell_, this),
       inspector_service_factory_(this),
-      debugger_id_(s_next_debugger_id++),
-      weak_factory_(this) {
+      weak_factory_(this),
+      debugger_id_(s_next_debugger_id++) {
   exported_services_.AddService(&view_manager_client_factory_);
   mojo::WeakBindToPipe(&exported_services_, provider.PassMessagePipe());
 }
@@ -135,6 +135,10 @@ void DocumentView::initializeLayerTreeView() {
   layer_host_->SetRootLayer(root_layer_);
 }
 
+void DocumentView::GetPixelsForTesting(std::vector<unsigned char>* pixels) {
+  return layer_host_->GetPixelsForTesting(pixels);
+}
+
 mojo::Shell* DocumentView::GetShell() {
   return shell_;
 }