MacViews a11y: Sync VoiceOver cursor with keyboard focus.

ui/views/view.h

 // 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.
 
 #ifndef UI_VIEWS_VIEW_H_
 #define UI_VIEWS_VIEW_H_
 
 #include <stddef.h>
 
 #include <algorithm>
@@ skipping 927 matching lines @@
   // Invoked from DoDrag after the drag completes. This implementation does
   // nothing, and is intended for subclasses to do cleanup.
   virtual void OnDragDone();
 
   // Returns true if the mouse was dragged enough to start a drag operation.
   // delta_x and y are the distance the mouse was dragged.
   static bool ExceededDragThreshold(const gfx::Vector2d& delta);
 
   // Accessibility -------------------------------------------------------------
 
+  // Gets the NativeViewAccessibility instance for this view, and creates one if
+  // it doesn't yet exist.
+  NativeViewAccessibility* GetNativeViewAccessibility();

[tapted, 2016/09/26 05:19:18]

I'm unsure about this - we'll have to see what views OWNERS say. E.g. it's a bit
confusing having bith GetNativeViewAccessibility() and
GetNativeViewAccessible(). An alternative could be something like

  AXPlatformNodeCocoa root = hostedView_->GetNativeViewAccessible();
  AXPlatformNodeDelegate* delegate = [root getDelegate];  // Needs an
implementation of getDelegate.
  return delegate->GetFocus();

[Patti Lor, 2016/09/28 00:29:14]

I like your alternative, but I think it needs to be cross-platform - I use this
a lot in some of my other CLs (e.g. ignoring accessibility elements, see
https://codereview.chromium.org/2119413004/diff/100001/ui/views/accessibility...
if you want context). Is it gross to have NativeViewAccessibility keep a static
reference to all the instances? Or maybe just change the previously mentioned CL
etc to work for Mac-only?

[dmazzoni, 2016/09/29 16:06:15]

For context, the reason I didn't add GetNativeViewAccessibility() before was
that GetNativeViewAccessible() doesn't always return something based on
NativeViewAccessibility. In particular, WebView and NativeViewHost both
return something different.

So my first inclination is to try to keep that design.

See other comment.

[Patti Lor, 2016/10/04 05:45:14]

Ok, thanks for the context. I've deleted the changes to view.* for this CL since
they're no longer needed, and will investigate alternatives for use in my other
accessibility CLs.

+
   // Modifies |state| to reflect the current accessible state of this view.
   virtual void GetAccessibleState(ui::AXViewState* state) { }
 
   // Returns an instance of the native accessibility interface for this view.
   virtual gfx::NativeViewAccessible GetNativeViewAccessible();
 
   // Notifies assistive technology that an accessibility event has
   // occurred on this view, such as when the view is focused or when its
   // value changes. Pass true for |send_native_event| except for rare
   // cases where the view is a native control that's already sending a
@@ skipping 611 matching lines @@
   // Belongs to this view, but it's reference-counted on some platforms
   // so we can't use a scoped_ptr. It's dereferenced in the destructor.
   NativeViewAccessibility* native_view_accessibility_;
 
   DISALLOW_COPY_AND_ASSIGN(View);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_VIEW_H_