Try |View::HandleAccessibleAction| before falling back to fixed actions.

chrome/browser/ui/aura/accessibility/ax_tree_source_aura.h

 // 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.
 
 #ifndef CHROME_BROWSER_UI_AURA_ACCESSIBILITY_AX_TREE_SOURCE_AURA_H_
 #define CHROME_BROWSER_UI_AURA_ACCESSIBILITY_AX_TREE_SOURCE_AURA_H_
 
 #include <stdint.h>
 
 #include <map>
 #include <memory>
 
 #include "base/macros.h"
 #include "chrome/browser/ui/aura/accessibility/ax_root_obj_wrapper.h"
 #include "ui/accessibility/ax_tree_data.h"
 #include "ui/accessibility/ax_tree_source.h"
 
+namespace ui {
+struct AXActionData;
+}  // namespace ui
+
 namespace views {
 class AXAuraObjWrapper;
 }  // namespace views
 
 // This class exposes the views hierarchy as an accessibility tree permitting
 // use with other accessibility classes.
 class AXTreeSourceAura
     : public ui::AXTreeSource<views::AXAuraObjWrapper*,
                               ui::AXNodeData,
                               ui::AXTreeData> {
  public:
   AXTreeSourceAura();
   ~AXTreeSourceAura() override;
 
   // A set of actions invoked on an Aura view.
   void DoDefault(int32_t id);
   void Focus(int32_t id);
   void MakeVisible(int32_t id);
   void SetSelection(int32_t id, int32_t start, int32_t end);
   void ShowContextMenu(int32_t id);
+  bool HandleAccessibleAction(const ui::AXActionData& action);
 
   // AXTreeSource implementation.
   bool GetTreeData(ui::AXTreeData* data) const override;
   views::AXAuraObjWrapper* GetRoot() const override;
   views::AXAuraObjWrapper* GetFromId(int32_t id) const override;
   int32_t GetId(views::AXAuraObjWrapper* node) const override;
   void GetChildren(
       views::AXAuraObjWrapper* node,
       std::vector<views::AXAuraObjWrapper*>* out_children) const override;
   views::AXAuraObjWrapper* GetParent(
       views::AXAuraObjWrapper* node) const override;
   bool IsValid(views::AXAuraObjWrapper* node) const override;
   bool IsEqual(views::AXAuraObjWrapper* node1,
                views::AXAuraObjWrapper* node2) const override;
   views::AXAuraObjWrapper* GetNull() const override;
   void SerializeNode(views::AXAuraObjWrapper* node,
                      ui::AXNodeData* out_data) const override;
 
   // Useful for debugging.
   std::string ToString(views::AXAuraObjWrapper* root, std::string prefix);
 
  private:
   std::unique_ptr<AXRootObjWrapper> root_;
 
   DISALLOW_COPY_AND_ASSIGN(AXTreeSourceAura);
 };
 
 #endif  // CHROME_BROWSER_UI_AURA_ACCESSIBILITY_AX_TREE_SOURCE_AURA_H_