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

chrome/browser/ui/gtk/gtk_chrome_shrinkable_hbox.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/ui/gtk/gtk_chrome_shrinkable_hbox.h"
 
 #include <gtk/gtk.h>
 
 #include <algorithm>
 
@@ skipping 21 matching lines @@
 }
 
 void SumChildrenWidthRequisition(GtkWidget* child, gpointer userdata) {
   if (gtk_widget_get_visible(child)) {
     GtkRequisition req;
     gtk_widget_get_child_requisition(child, &req);
     (*reinterpret_cast<int*>(userdata)) += std::max(req.width, 0);
   }
 }
 
-void ShowInvisibleChildren(GtkWidget* child, gpointer userdata) {
-  if (!gtk_widget_get_visible(child)) {
-    gtk_widget_show(child);
-    ++(*reinterpret_cast<int*>(userdata));
-  }
-}
-
 void ChildSizeAllocate(GtkWidget* child, gpointer userdata) {
   if (!gtk_widget_get_visible(child))
     return;
 
   SizeAllocateData* data = reinterpret_cast<SizeAllocateData*>(userdata);
   GtkAllocation child_allocation;
   gtk_widget_get_allocation(child, &child_allocation);
 
   if (data->homogeneous) {
     // Make sure the child is not overlapped with others' boundary.
@@ skipping 222 matching lines @@
 
 gint gtk_chrome_shrinkable_hbox_get_visible_child_count(
     GtkChromeShrinkableHBox* box) {
   gint visible_children_count = 0;
   gtk_container_foreach(GTK_CONTAINER(box), CountVisibleChildren,
                         &visible_children_count);
   return visible_children_count;
 }
 
 G_END_DECLS