Add a Display and ContextProvider concept to mojom, use to recreate

examples/surfaces_app/child_gl_impl.cc

Index: examples/surfaces_app/child_gl_impl.cc
diff --git a/examples/surfaces_app/child_gl_impl.cc b/examples/surfaces_app/child_gl_impl.cc
index 4e22df3eeb4fe3f38635d81f8f480f9dac7b6150..97cd9a13d2f02db62d4105aa908354dd0a7939bd 100644
--- a/examples/surfaces_app/child_gl_impl.cc
+++ b/examples/surfaces_app/child_gl_impl.cc
@@ -78,7 +78,8 @@ void ChildGLImpl::ProduceFrame(ColorPtr color,
                                const ProduceCallback& callback) {
   color_ = color.To<SkColor>();
   size_ = size.To<gfx::Size>();
-  cube_.Init(size_.width(), size_.height());
+  cube_.Init();
+  cube_.set_size(size_.width(), size_.height());
   cube_.set_color(
       SkColorGetR(color_), SkColorGetG(color_), SkColorGetB(color_));
   surface_->CreateSurface(local_id_);