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

ash/accelerators/accelerator_controller.cc

Index: ash/accelerators/accelerator_controller.cc
diff --git a/ash/accelerators/accelerator_controller.cc b/ash/accelerators/accelerator_controller.cc
index 1392b344907eaf2f629cb436c6302756a69ac95d..0c072dbb2c4c52112a36fa9bdee3ee81727f5e65 100644
--- a/ash/accelerators/accelerator_controller.cc
+++ b/ash/accelerators/accelerator_controller.cc
@@ -285,7 +285,7 @@ bool HandleRotateScreen() {
 }
 
 bool HandleToggleRootWindowFullScreen() {
-  Shell::GetPrimaryRootWindow()->GetDispatcher()->ToggleFullScreen();
+  Shell::GetPrimaryRootWindow()->GetDispatcher()->host()->ToggleFullScreen();
   return true;
 }