Split surface id and simplify connecting to surfaces service

examples/surfaces_app/embedder.cc

Index: examples/surfaces_app/embedder.cc
diff --git a/examples/surfaces_app/embedder.cc b/examples/surfaces_app/embedder.cc
index f958c4dd6f604fbd259586df5f163642d3cf67f0..cd8335c5662f6563ba2e48f2b438e87850bb2acc 100644
--- a/examples/surfaces_app/embedder.cc
+++ b/examples/surfaces_app/embedder.cc
@@ -27,7 +27,7 @@ using cc::SolidColorDrawQuad;
 using cc::DelegatedFrameData;
 using cc::CompositorFrame;
 
-Embedder::Embedder(Surface* surface) : surface_(surface) {
+Embedder::Embedder() : surface_(nullptr) {
 }
 
 Embedder::~Embedder() {
@@ -89,7 +89,7 @@ void Embedder::ProduceFrame(cc::SurfaceId child_one,
   scoped_ptr<CompositorFrame> frame(new CompositorFrame);
   frame->delegated_frame_data = delegated_frame_data.Pass();
 
-  surface_->SubmitFrame(mojo::SurfaceId::From(id_), mojo::Frame::From(*frame),
+  surface_->SubmitFrame(id_.Clone(), mojo::Frame::From(*frame),
                         mojo::Closure());
 }