Move context-related callbacks into OutputSurface

cc/layer_tree_host_impl.cc

Index: cc/layer_tree_host_impl.cc
diff --git a/cc/layer_tree_host_impl.cc b/cc/layer_tree_host_impl.cc
index bcd3248581d46baca373158376149adc06323798..477f144bd5bb25caca4550f7fc4e3761688c1aec 100644
--- a/cc/layer_tree_host_impl.cc
+++ b/cc/layer_tree_host_impl.cc
@@ -1245,6 +1245,8 @@ bool LayerTreeHostImpl::InitializeRenderer(
   resource_provider_ = resource_provider.Pass();
   output_surface_ = output_surface.Pass();
 
+  output_surface_->RegisterCallbacks();

[piman, 2013/03/15 03:20:38]

It's rather unfortunate that we have this very complicated dance to initialize
the OutputSurface, which is at the API boundary.

What would it take for the callbacks to not behave badly if we were setting them
at Bind time?

+
   if (!visible_)
     renderer_->SetVisible(visible_);