Tab audio mute control (views UI), behind a switch (off by default).

chrome/browser/ui/tabs/tab_menu_model.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/tabs/tab_menu_model.h"
 
 #include "base/command_line.h"
 #include "chrome/browser/ui/tabs/tab_strip_model.h"
 #include "chrome/browser/ui/tabs/tab_strip_model_delegate.h"
+#include "chrome/browser/ui/tabs/tab_utils.h"
 #include "chrome/grit/generated_resources.h"
 
 TabMenuModel::TabMenuModel(ui::SimpleMenuModel::Delegate* delegate,
                            TabStripModel* tab_strip,
                            int index)
     : ui::SimpleMenuModel(delegate) {
   Build(tab_strip, index);
 }
 
 void TabMenuModel::Build(TabStripModel* tab_strip, int index) {
   bool affects_multiple_tabs =
       (tab_strip->IsTabSelected(index) &&
        tab_strip->selection_model().selected_indices().size() > 1);
   AddItemWithStringId(TabStripModel::CommandNewTab, IDS_TAB_CXMENU_NEWTAB);
   AddSeparator(ui::NORMAL_SEPARATOR);
   AddItemWithStringId(TabStripModel::CommandReload, IDS_TAB_CXMENU_RELOAD);
   AddItemWithStringId(TabStripModel::CommandDuplicate,
                       IDS_TAB_CXMENU_DUPLICATE);
   bool will_pin = tab_strip->WillContextMenuPin(index);
   if (affects_multiple_tabs) {
     AddItemWithStringId(
         TabStripModel::CommandTogglePinned,
         will_pin ? IDS_TAB_CXMENU_PIN_TABS : IDS_TAB_CXMENU_UNPIN_TABS);
   } else {
     AddItemWithStringId(
         TabStripModel::CommandTogglePinned,
         will_pin ? IDS_TAB_CXMENU_PIN_TAB : IDS_TAB_CXMENU_UNPIN_TAB);
   }
+  if (chrome::IsTabAudioMutingFeatureEnabled()) {
+    if (affects_multiple_tabs) {
+      const bool will_mute = !chrome::AreAllTabsMuted(
+          *tab_strip, tab_strip->selection_model().selected_indices());
+      AddItemWithStringId(
+          TabStripModel::CommandToggleTabAudioMuted,
+          will_mute ? IDS_TAB_CXMENU_AUDIO_MUTE_TABS :
+              IDS_TAB_CXMENU_AUDIO_UNMUTE_TABS);
+    } else {
+      const bool will_mute =
+          !chrome::IsTabAudioMuted(tab_strip->GetWebContentsAt(index));
+      AddItemWithStringId(
+          TabStripModel::CommandToggleTabAudioMuted,
+          will_mute ? IDS_TAB_CXMENU_AUDIO_MUTE_TAB :
+              IDS_TAB_CXMENU_AUDIO_UNMUTE_TAB);
+    }
+  }
   AddSeparator(ui::NORMAL_SEPARATOR);
   if (affects_multiple_tabs) {
     AddItemWithStringId(TabStripModel::CommandCloseTab,
                         IDS_TAB_CXMENU_CLOSETABS);
   } else {
     AddItemWithStringId(TabStripModel::CommandCloseTab,
                         IDS_TAB_CXMENU_CLOSETAB);
   }
   AddItemWithStringId(TabStripModel::CommandCloseOtherTabs,
                       IDS_TAB_CXMENU_CLOSEOTHERTABS);
   AddItemWithStringId(TabStripModel::CommandCloseTabsToRight,
                       IDS_TAB_CXMENU_CLOSETABSTORIGHT);
   AddSeparator(ui::NORMAL_SEPARATOR);
   const bool is_window = tab_strip->delegate()->GetRestoreTabType() ==
       TabStripModelDelegate::RESTORE_WINDOW;
   AddItemWithStringId(TabStripModel::CommandRestoreTab,
                       is_window ? IDS_RESTORE_WINDOW : IDS_RESTORE_TAB);
   AddItemWithStringId(TabStripModel::CommandBookmarkAllTabs,
                       IDS_TAB_CXMENU_BOOKMARK_ALL_TABS);
 }