Mac a11y: Add Help, TopLevelUIElement, and Window accessibility attributes.

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 287 matching lines @@
     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,
 
     // Attributes which are not required, but are general to all roles.
     NSAccessibilityRoleDescriptionAttribute,
     NSAccessibilityEnabledAttribute,
     NSAccessibilityFocusedAttribute,
+    NSAccessibilityHelpAttribute,
+    NSAccessibilityTopLevelUIElementAttribute,
+    NSAccessibilityWindowAttribute,
   ];
 
   // Attributes required for user-editable controls.
   NSArray* const kValueAttributes = @[ NSAccessibilityValueAttribute ];
 
   // Attributes required for textfields.
   NSArray* const kTextfieldAttributes = @[
     NSAccessibilityInsertionPointLineNumberAttribute,
     NSAccessibilityNumberOfCharactersAttribute,
     NSAccessibilityPlaceholderValueAttribute,
@@ skipping 75 matching lines @@
                                      ui::AX_STATE_PROTECTED))
         return NSAccessibilitySecureTextFieldSubrole;
       break;
     default:
       break;
   }
   return [AXPlatformNodeCocoa nativeSubroleFromAXRole:role];
 }
 
 - (NSString*)AXRoleDescription {
-  NSString* description = [self getStringAttribute:ui::AX_ATTR_DESCRIPTION];
-  if (!description)
-    return NSAccessibilityRoleDescription([self AXRole], [self AXSubrole]);
-  return description;
+  return NSAccessibilityRoleDescription([self AXRole], [self AXSubrole]);
 }
 
 - (NSValue*)AXSize {
   return [NSValue valueWithSize:self.boundsInScreen.size];
 }
 
 - (NSString*)AXTitle {
   return [self getStringAttribute:ui::AX_ATTR_NAME];
 }
 
 - (NSString*)AXValue {
   return [self getStringAttribute:ui::AX_ATTR_VALUE];
 }
 
 - (NSValue*)AXEnabled {
   return [NSNumber
       numberWithBool:!ui::AXViewState::IsFlagSet(node_->GetData().state,
                                                  ui::AX_STATE_DISABLED)];
 }
 
 - (NSValue*)AXFocused {
   if (ui::AXViewState::IsFlagSet(node_->GetData().state,
                                  ui::AX_STATE_FOCUSABLE))
     return [NSNumber numberWithBool:(node_->GetDelegate()->GetFocus() ==
                                      node_->GetNativeViewAccessible())];
   return [NSNumber numberWithBool:NO];
 }
 
+- (NSString*)AXHelp {
+  return [self getStringAttribute:ui::AX_ATTR_DESCRIPTION];
+}
+
+- (NSWindow*)AXTopLevelUIElement {
+  return [self AXWindow];
+}
+
+- (NSWindow*)AXWindow {
+  return node_->GetDelegate()->GetTopLevelWidget();
+}
+
 // Textfield-specific NSAccessibility attributes.
 
 - (NSNumber*)AXInsertionPointLineNumber {
   // Multiline is not supported on views.
   return [NSNumber numberWithInteger:0];
 }
 
 - (NSNumber*)AXNumberOfCharacters {
   return [NSNumber numberWithInteger:[[self AXValue] length]];
 }
@@ skipping 75 matching lines @@
   }
   NotifyMacEvent(target, event_type);
 }
 
 int AXPlatformNodeMac::GetIndexInParent() {
   // TODO(dmazzoni): implement this.  http://crbug.com/396137
   return -1;
 }
 
 }  // namespace ui