MacViews a11y: Allow accessibility clients to set the AXValue on some controls.

ui/accessibility/platform/test_ax_node_wrapper.h

 // Copyright 2015 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 UI_ACCESSIBILITY_PLATFORM_TEST_AX_NODE_WRAPPER_H_
 #define UI_ACCESSIBILITY_PLATFORM_TEST_AX_NODE_WRAPPER_H_
 
 #include "ui/accessibility/ax_node.h"
 #include "ui/accessibility/ax_tree.h"
 #include "ui/accessibility/platform/ax_platform_node.h"
@@ skipping 22 matching lines @@
   gfx::NativeWindow GetTopLevelWidget() override;
   gfx::NativeViewAccessible GetParent() override;
   int GetChildCount() override;
   gfx::NativeViewAccessible ChildAtIndex(int index) override;
   gfx::Vector2d GetGlobalCoordinateOffset() override;
   gfx::NativeViewAccessible HitTestSync(int x, int y) override;
   gfx::NativeViewAccessible GetFocus() override;
   gfx::AcceleratedWidget GetTargetForNativeAccessibilityEvent() override;
   void DoDefaultAction() override;
   bool SetStringValue(const base::string16& new_value) override;
+  bool CanSetStringValue() override;
 
  private:
   TestAXNodeWrapper(AXTree* tree, AXNode* node);
 
   AXTree* tree_;
   AXNode* node_;
   AXPlatformNode* platform_node_;
 };
 
 }  // namespace ui
 
 #endif  // UI_ACCESSIBILITY_PLATFORM_TEST_AX_NODE_WRAPPER_H_