UpdateZoomControls honors the global enabled state of the zoom commands....

chrome/browser/views/wrench_menu.cc

 // Copyright (c) 2010 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/views/wrench_menu.h"
 
 #include <cmath>
 
 #include "app/l10n_util.h"
 #include "app/resource_bundle.h"
@@ skipping 438 matching lines @@
                        const NotificationDetails& details) {
     DCHECK_EQ(NotificationType::ZOOM_LEVEL_CHANGED, type.value);
     UpdateZoomControls();
   }
 
  private:
   void UpdateZoomControls() {
     bool enable_increment, enable_decrement;
     int zoom_percent =
         static_cast<int>(GetZoom(&enable_increment, &enable_decrement));
+    enable_increment = enable_increment &&
+        menu_model_->IsEnabledAt(increment_button_->tag());
+    enable_decrement = enable_decrement &&
+        menu_model_->IsEnabledAt(decrement_button_->tag());
+    increment_button_->SetEnabled(enable_increment);
+    decrement_button_->SetEnabled(enable_decrement);
     zoom_label_->SetText(l10n_util::GetStringF(
                              IDS_ZOOM_PERCENT, IntToWString(zoom_percent)));
-    increment_button_->SetEnabled(enable_increment);
-    decrement_button_->SetEnabled(enable_decrement);
+    // If both increment and decrement are disabled, then we disable the zoom
+    // label too.
+    zoom_label_->SetEnabled(enable_increment || enable_decrement);
   }
 
   double GetZoom(bool* enable_increment, bool* enable_decrement) {
     // TODO: move this somewhere it can be shared.
     TabContents* selected_tab = menu_->browser_->GetSelectedTabContents();
     *enable_decrement = *enable_increment = false;
     if (!selected_tab)
       return 1;
 
     HostZoomMap* zoom_map = selected_tab->profile()->GetHostZoomMap();
@@ skipping 219 matching lines @@
   }
 
   return menu_item;
 }
 
 void WrenchMenu::CancelAndEvaluate(MenuModel* model, int index) {
   selected_menu_model_ = model;
   selected_index_ = index;
   root_->Cancel();
 }