MacViews/a11y: Ignore invisible accessibility elements.

ui/accessibility/platform/ax_platform_node_mac.mm

 // 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.
 
 #import "ui/accessibility/platform/ax_platform_node_mac.h"
 
 #import <Cocoa/Cocoa.h>
 #include <stddef.h>
 
 #include "base/macros.h"
@@ skipping 261 matching lines @@
 - (NSString*)getStringAttribute:(ui::AXStringAttribute)attribute {
   std::string attributeValue;
   if (node_->GetStringAttribute(attribute, &attributeValue))
     return base::SysUTF8ToNSString(attributeValue);
   return nil;
 }
 
 // NSAccessibility informal protocol implementation.
 
 - (BOOL)accessibilityIsIgnored {
-  return [[self AXRole] isEqualToString:NSAccessibilityUnknownRole];
+  return [[self AXRole] isEqualToString:NSAccessibilityUnknownRole] ||
+         node_->GetData().HasStateFlag(ui::AX_STATE_INVISIBLE);
 }
 
 - (id)accessibilityHitTest:(NSPoint)point {
   for (AXPlatformNodeCocoa* child in [self AXChildren]) {
     if (NSPointInRect(point, child.boundsInScreen))
       return [child accessibilityHitTest:point];
   }
   return NSAccessibilityUnignoredAncestor(self);
 }
 
 - (BOOL)accessibilityNotifiesWhenDestroyed {
   return YES;
 }
 
 - (id)accessibilityFocusedUIElement {
   return node_->GetDelegate()->GetFocus();
 }
 
 - (NSArray*)accessibilityActionNames {
   return nil;
 }
 
 - (NSArray*)accessibilityAttributeNames {
   // These attributes are required on all accessibility objects.
   NSArray* const kAllRoleAttributes = @[
     NSAccessibilityChildrenAttribute,

[tapted, 2016/12/13 05:57:51]

There's also NSAccessibilityVisibleChildrenAttribute .
browser_accessibility_cocoa.mm uses this. Perhaps by providing it, AppKit will
prefer it over AXChildren?  But also AXVisibleChildren says "Recommended for
elements whose child elements can be occluded or scrolled out of view." so that
might not be what we want.

There's also AXHidden.. but I think that's "is the app hidden?" and not intended
for UI elements :/

[Patti Lor, 2016/12/13 06:13:19]

Yeah, not sure either - thanks for looking into it though, I hadn't known about
those attributes.

[dmazzoni, 2016/12/13 17:37:01]

Yeah, I believe AXVisibleChildren is only used for things like list boxes and
tables.

[Patti Lor, 2016/12/13 23:40:04]

Ack - thanks for the info, will keep that in mind for future changes.

     NSAccessibilityParentAttribute,
     NSAccessibilityPositionAttribute,
     NSAccessibilityRoleAttribute,
     NSAccessibilitySizeAttribute,
     NSAccessibilitySubroleAttribute,
 
     // Title is required for most elements. Cocoa asks for the value even if it
     // is omitted here, but won't present it to accessibility APIs without this.
     NSAccessibilityTitleAttribute,
 
@@ skipping 276 matching lines @@
   }
   NotifyMacEvent(native_node_, event_type);
 }
 
 int AXPlatformNodeMac::GetIndexInParent() {
   // TODO(dmazzoni): implement this.  http://crbug.com/396137
   return -1;
 }
 
 }  // namespace ui