Remove some pass-thrus on RootWindow API in favor of exposing the RootWindowHost again.

ui/aura/bench/bench_main.cc

Index: ui/aura/bench/bench_main.cc
diff --git a/ui/aura/bench/bench_main.cc b/ui/aura/bench/bench_main.cc
index 9ebfb3931c814172b2c66f56b9d0e68199d759d4..8b85f7d1571470348627a05f57784291175ddeb9 100644
--- a/ui/aura/bench/bench_main.cc
+++ b/ui/aura/bench/bench_main.cc
@@ -363,7 +363,7 @@ int main(int argc, char** argv) {
   ui::PrintLayerHierarchy(root_window->window()->layer(), gfx::Point(100, 100));
 #endif
 
-  root_window->ShowRootWindow();
+  root_window->host()->Show();
   base::MessageLoopForUI::current()->Run();
   focus_client.reset();
   root_window.reset();