Get rid of the EnableClose() infrastructure in Widget.

ui/aura_shell/toplevel_frame_view.cc

Index: ui/aura_shell/toplevel_frame_view.cc
===================================================================
--- ui/aura_shell/toplevel_frame_view.cc	(revision 111086)
+++ ui/aura_shell/toplevel_frame_view.cc	(working copy)
@@ -161,11 +161,6 @@
     return HTNOWHERE;
   }
 
-  // Updates the enabled state of the close button.
-  void EnableClose(bool enable) {
-    close_button_->SetEnabled(enable);
-  }
-
   // Overridden from FrameComponent:
   virtual bool IgnoreEventsForPoint(const gfx::Point& point) OVERRIDE {
     gfx::Point translated_point(point);
@@ -401,10 +396,6 @@
   // Nothing.
 }
 
-void ToplevelFrameView::EnableClose(bool enable) {
-  caption_->EnableClose(enable);
-}
-
 void ToplevelFrameView::ResetWindowControls() {
   NOTIMPLEMENTED();
 }