Expose media controls to accessibility

chrome/common/extensions/api/automation_internal.idl

 // 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 is the implementation layer of the chrome.automation API, and is
 // essentially a translation of the internal accessibility tree update system
 // into an extension API.
 namespace automationInternal {
   // Data for an accessibility event and/or an atomic change to an accessibility
   // tree. See ui/accessibility/ax_tree_update.h for an extended explanation of
@@ skipping 18 matching lines @@
 
   // All possible actions that can be performed on automation nodes.
   enum ActionType {
     focus,
     doDefault,
     getImageData,
     makeVisible,
     setAccessibilityFocus,
     setSequentialFocusNavigationStartingPoint,
     setSelection,
+    startDucking,
+    stopDucking,
     showContextMenu
   };
 
   // Arguments required for all actions supplied to performAction.
   dictionary PerformActionRequiredParams {
     long treeID;
     long automationNodeID;
     ActionType actionType;
   };
 
@@ skipping 69 matching lines @@
                              long nodeID,
                              DOMString changeType);
 
     static void onChildTreeID(long treeID, long nodeID);
 
     static void onNodesRemoved(long treeID, long[] nodeIDs);
 
     static void onAccessibilityTreeSerializationError(long treeID);
   };
 };