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

tools/metrics/actions/actions.xml

 <!--
 Copyright 2014 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.
 -->
 
 <!--
 This file is a comprehensive list of Chrome user actions along with the owner
 and description for each user action.
 
@@ skipping 2025 matching lines @@
 <action name="CloseTabByKey">
   <owner>Please list the metric's owners. Add more owner tags as needed.</owner>
   <description>Please enter the description of this user action.</description>
 </action>
 
 <action name="CloseTab_Accelerator">
   <owner>Please list the metric's owners. Add more owner tags as needed.</owner>
   <description>Please enter the description of this user action.</description>
 </action>
 
+<action name="CloseTab_AudioIndicator">
+  <owner>miu@chromium.org</owner>
+  <description>
+    User clicked the close tab button; the audio indicator was showing.
+  </description>
+</action>
+
 <action name="CloseTab_Mouse">
   <owner>Please list the metric's owners. Add more owner tags as needed.</owner>
   <description>Please enter the description of this user action.</description>
 </action>
 
+<action name="CloseTab_MuteToggleAvailable">
+  <owner>miu@chromium.org</owner>
+  <description>
+    User clicked the close tab button; the audio mute toggle button was enabled.
+  </description>
+</action>
+
+<action name="CloseTab_NoMediaIndicator">
+  <owner>miu@chromium.org</owner>
+  <description>
+    User clicked the close tab button; the media indicator was not showing.
+  </description>
+</action>
+
+<action name="CloseTab_RecordingIndicator">
+  <owner>miu@chromium.org</owner>
+  <description>
+    User clicked the close tab button; the recording/capture indicator was
+    showing.
+  </description>
+</action>
+
 <action name="CloseWebApp">
   <owner>Please list the metric's owners. Add more owner tags as needed.</owner>
   <description>Please enter the description of this user action.</description>
 </action>
 
 <action name="CloseWindow">
   <owner>Please list the metric's owners. Add more owner tags as needed.</owner>
   <description>Please enter the description of this user action.</description>
 </action>
 
@@ skipping 5004 matching lines @@
 <action name="MediaContextMenu_Play">
   <owner>Please list the metric's owners. Add more owner tags as needed.</owner>
   <description>Please enter the description of this user action.</description>
 </action>
 
 <action name="MediaContextMenu_Unmute">
   <owner>Please list the metric's owners. Add more owner tags as needed.</owner>
   <description>Please enter the description of this user action.</description>
 </action>
 
+<action name="MediaIndicatorButton_Dragged">
+  <owner>miu@chromium.org</owner>
+  <description>
+    User dragged the tab media indicator button; perhaps meant to drag the tab.
+  </description>
+</action>
+
 <action name="Menu_Take_Screenshot">
   <owner>Please list the metric's owners. Add more owner tags as needed.</owner>
   <description>Please enter the description of this user action.</description>
 </action>
 
 <action name="MinButton_Clk">
   <owner>Please list the metric's owners. Add more owner tags as needed.</owner>
   <description>Please enter the description of this user action.</description>
 </action>
 
@@ skipping 775 matching lines @@
 <action name="MoveWordLeft">
   <owner>Please list the metric's owners. Add more owner tags as needed.</owner>
   <description>Please enter the description of this user action.</description>
 </action>
 
 <action name="MoveWordRight">
   <owner>Please list the metric's owners. Add more owner tags as needed.</owner>
   <description>Please enter the description of this user action.</description>
 </action>
 
+<action name="MuteTab">
+  <owner>miu@chromium.org</owner>
+  <description>
+    User clicked the tab audio indicator to mute the tab.
+  </description>
+</action>
+
 <action name="NTPPromoClosed">
   <owner>Please list the metric's owners. Add more owner tags as needed.</owner>
   <description>Please enter the description of this user action.</description>
 </action>
 
 <action name="NTPPromoShown">
   <owner>Please list the metric's owners. Add more owner tags as needed.</owner>
   <description>Please enter the description of this user action.</description>
 </action>
 
@@ skipping 2931 matching lines @@
 <action name="TabContextMenu_CompactNavigationBar">
   <owner>Please list the metric's owners. Add more owner tags as needed.</owner>
   <description>Please enter the description of this user action.</description>
 </action>
 
 <action name="TabContextMenu_Duplicate">
   <owner>Please list the metric's owners. Add more owner tags as needed.</owner>
   <description>Please enter the description of this user action.</description>
 </action>
 
+<action name="TabContextMenu_MuteTabs">
+  <owner>miu@chromium.org</owner>
+  <description>
+    User muted one or more tabs via the tab context menu.
+  </description>
+</action>
+
 <action name="TabContextMenu_NewTab">
   <owner>Please list the metric's owners. Add more owner tags as needed.</owner>
   <description>Please enter the description of this user action.</description>
 </action>
 
 <action name="TabContextMenu_OpenTabsLeftToRight">
   <owner>Please list the metric's owners. Add more owner tags as needed.</owner>
   <description>Please enter the description of this user action.</description>
 </action>
 
@@ skipping 10 matching lines @@
 <action name="TabContextMenu_RestoreTab">
   <owner>Please list the metric's owners. Add more owner tags as needed.</owner>
   <description>Please enter the description of this user action.</description>
 </action>
 
 <action name="TabContextMenu_TogglePinned">
   <owner>Please list the metric's owners. Add more owner tags as needed.</owner>
   <description>Please enter the description of this user action.</description>
 </action>
 
+<action name="TabContextMenu_UnmuteTabs">
+  <owner>miu@chromium.org</owner>
+  <description>
+    User unmuted one or more tabs via the tab context menu.
+  </description>
+</action>
+
 <action name="TabContextMenu_UseDestinationsTab_Off">
   <owner>Please list the metric's owners. Add more owner tags as needed.</owner>
   <description>Please enter the description of this user action.</description>
 </action>
 
 <action name="TabContextMenu_UseDestinationsTab_On">
   <owner>Please list the metric's owners. Add more owner tags as needed.</owner>
   <description>Please enter the description of this user action.</description>
 </action>
 
 <action name="TabContextMenu_UseVerticalTabs">
   <owner>Please list the metric's owners. Add more owner tags as needed.</owner>
   <description>Please enter the description of this user action.</description>
 </action>
 
+<action name="TabMediaIndicator_Clicked">
+  <owner>miu@chromium.org</owner>
+  <description>
+    User clicked the tab media indicator; this will have no effect.
+  </description>
+</action>
+
 <action name="TabOverview_DetachCell">
   <owner>Please list the metric's owners. Add more owner tags as needed.</owner>
   <description>Please enter the description of this user action.</description>
 </action>
 
 <action name="TabOverview_DragCell">
   <owner>Please list the metric's owners. Add more owner tags as needed.</owner>
   <description>Please enter the description of this user action.</description>
 </action>
 
@@ skipping 185 matching lines @@
 <action name="Undo">
   <owner>Please list the metric's owners. Add more owner tags as needed.</owner>
   <description>Please enter the description of this user action.</description>
 </action>
 
 <action name="Unlink">
   <owner>Please list the metric's owners. Add more owner tags as needed.</owner>
   <description>Please enter the description of this user action.</description>
 </action>
 
+<action name="UnmuteTab">
+  <owner>miu@chromium.org</owner>
+  <description>
+    User clicked the tab audio muting indicator to unmute the tab.
+  </description>
+</action>
+
 <action name="Unselect">
   <owner>Please list the metric's owners. Add more owner tags as needed.</owner>
   <description>Please enter the description of this user action.</description>
 </action>
 
 <action name="UpdateChrome">
   <owner>Please list the metric's owners. Add more owner tags as needed.</owner>
   <description>Please enter the description of this user action.</description>
 </action>
 
@@ skipping 441 matching lines @@
     apple-mobile-webapp-capable meta tag.
   </description>
 </action>
 
 <action name="webapps.AddShortcut.Bookmark">
   <owner>dfalcantara@chromium.org</owner>
   <description>Shortcut added to the homescreen for a bookmark.</description>
 </action>
 
 </actions>