Fixes for -Wunused-function on Linux, Android and ChromeOS

ui/views/widget/native_widget_aura.cc

Index: ui/views/widget/native_widget_aura.cc
diff --git a/ui/views/widget/native_widget_aura.cc b/ui/views/widget/native_widget_aura.cc
index 92f4b99a7d1d9ebd7014b01d980dde82fde0a1bd..ba6954d752e4c4262d55fd793d771dd1e93cff14 100644
--- a/ui/views/widget/native_widget_aura.cc
+++ b/ui/views/widget/native_widget_aura.cc
@@ -973,6 +973,7 @@ void Widget::NotifyLocaleChanged() {
 }
 
 namespace {
+#if defined(OS_WIN) || (defined(USE_X11) && !defined(OS_CHROMEOS))
 void CloseWindow(aura::Window* window) {
   if (window) {
     Widget* widget = Widget::GetWidgetForNativeView(window);
@@ -984,6 +985,8 @@ void CloseWindow(aura::Window* window) {
       widget->CloseNow();
   }
 }
+#endif
+
 #if defined(OS_WIN)
 BOOL CALLBACK WindowCallbackProc(HWND hwnd, LPARAM lParam) {
   aura::Window* root_window =