views/mus: Create the BitmapUploader only when needed.

ui/views/mus/surface_binding.cc

Index: ui/views/mus/surface_binding.cc
diff --git a/ui/views/mus/surface_binding.cc b/ui/views/mus/surface_binding.cc
index 415e115535cdc3714697f28e58b12dcb913465bb..affe53d4d4c3d656cc8c3caf6365e1d73c9d571c 100644
--- a/ui/views/mus/surface_binding.cc
+++ b/ui/views/mus/surface_binding.cc
@@ -79,6 +79,9 @@ base::LazyInstance<base::ThreadLocalPointer<
 SurfaceBinding::PerClientState* SurfaceBinding::PerClientState::Get(
     shell::Connector* connector,
     mus::WindowTreeClient* client) {
+  // |connector| can be null in some unit-tests.
+  if (!connector)
+    return nullptr;
   ClientToStateMap* window_map = window_states.Pointer()->Get();
   if (!window_map) {
     window_map = new ClientToStateMap;
@@ -146,7 +149,7 @@ SurfaceBinding::SurfaceBinding(shell::Connector* connector,
 SurfaceBinding::~SurfaceBinding() {}
 
 std::unique_ptr<cc::OutputSurface> SurfaceBinding::CreateOutputSurface() {
-  return state_->CreateOutputSurface(window_, surface_type_);
+  return state_ ? state_->CreateOutputSurface(window_, surface_type_) : nullptr;
 }
 
 }  // namespace views