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

ui/views/corewm/tooltip_aura.cc

Index: ui/views/corewm/tooltip_aura.cc
diff --git a/ui/views/corewm/tooltip_aura.cc b/ui/views/corewm/tooltip_aura.cc
index 8ba23935638bdbbe191d5c2135d1d8f8c0d63cec..7988ebee57ef28ac792825f2e93974b9ecfa7759 100644
--- a/ui/views/corewm/tooltip_aura.cc
+++ b/ui/views/corewm/tooltip_aura.cc
@@ -173,9 +173,7 @@ gfx::Rect TooltipAura::GetBoundsForTooltip(
   // (which comes from the RootWindow).
   if (screen_type_ == gfx::SCREEN_TYPE_NATIVE &&
       gfx::SCREEN_TYPE_NATIVE != gfx::SCREEN_TYPE_ALTERNATE) {
-    aura::WindowEventDispatcher* dispatcher = tooltip_window_->GetDispatcher();
-    widget_bounds = gfx::Rect(dispatcher->GetHostOrigin(),
-                              dispatcher->GetHostSize());
+    widget_bounds = tooltip_window_->GetDispatcher()->host()->GetBounds();
   }
   gfx::Screen* screen = gfx::Screen::GetScreenByType(screen_type_);
   gfx::Rect bounds(screen->GetDisplayNearestPoint(origin).bounds());